Block interlocking splicing type rocket body thermal insulation layer and preparation method thereof

Abstract

The invention discloses a block interlocking splicing type rocket body thermal insulation layer and a preparation method thereof, belongs to the technical field of thermal insulation materials, and solves the technical problems of'splicing heat leakage, weak structure, poor adaptation 'and the like of a traditional rocket material thermal insulation layer in the prior art. A rocket body heat preservation layer is a cylindrical heat preservation structure layer which is formed by splicing and enclosing main body heat preservation block interlocking splicing type structures and matched with the outer side wall of a rocket body. The block interlocking splicing type structure is a step inclined table interlocking splicing structure, so that surface contact type splicing-step interlocking surfaces are formed among the main body heat preservation blocks. A rocket body thermal insulation layer scheme of'block foaming polyurethane foam with a stepped sloping bench interlocking structure, gradient bonding and integrated reinforcement 'is provided, precise foaming of complex blocks is realized through a customized mold, and a stepped sloping bench splicing and reinforcing process is combined.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation materials technology, specifically to a modular interlocking splicing type thermal insulation layer for rocket bodies and its preparation method. Background Technology

[0002] Existing rocket insulation layers utilize materials such as cork chips, MLI (multilayer insulation material), aluminosilicate wool, and ceramic matrix composites. Each of these materials has its own technical drawbacks, broadly categorized as follows: Unstable insulation performance: Cork chips are prone to moisture absorption, leading to fluctuations in thermal conductivity; MLI's insulation efficiency drops by 90% due to air convection in atmospheric environments; aluminosilicate wool suffers from fiber sintering at high temperatures and moisture absorption and freeze-thaw expansion at low temperatures, making it impossible to maintain stable insulation performance. Insufficient structural reliability: The bonding interface between cork chips and MLI is prone to detachment due to thermal expansion and contraction or vibration and impact, resulting in uncontrolled localized heat and cold conduction. Complex and costly processes: Ceramic matrix composites require high-temperature and high-pressure molding; multilayer MLI installation relies on manual alignment, resulting in gaps and the risk of detachment, leading to low yield rates; cork chips require pre-treatment for moisture protection. Summary of the Invention

[0003] In view of the shortcomings and deficiencies of the prior art, the present invention provides a modular interlocking splicing rocket body insulation layer and its preparation method. In summary, the present invention solves the core problems of traditional insulation layers such as "heat leakage at splicing, weak structure and poor compatibility", suppresses the delamination failure of the "foam-fiber cloth" interface at the splicing point, and achieves synergistic optimization of "lightweight, vibration resistance, impact resistance and interface stability". It has both technological advancement and economic feasibility.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: The present invention provides a segmented interlocking spliced ​​rocket body insulation layer, wherein the rocket body insulation layer is a cylindrical insulation structure layer that is spliced ​​together by segmented interlocking spliced ​​main insulation structure and matches the outer wall of the rocket body. The modular interlocking splicing structure adopts a stepped inclined platform interlocking splicing structure, so that the main insulation blocks form a surface contact splicing - stepped interlocking surface. The main insulation block has a hexahedral structure, including inner sidewall, outer sidewall, left sidewall, right sidewall, upper sidewall and lower sidewall; Its inner and outer walls are curved surfaces that match the outer wall of the rocket body. The left and right sides are respectively provided with a first micro positioning boss and a second micro positioning boss, and the micro positioning boss and the side wall on the same side form a transverse locking groove. The micro positioning boss on the same side and the transverse locking groove are connected to form a transverse insertion surface. The first micro positioning boss and the second micro positioning boss are not symmetrically arranged and are close to the inner side wall and the outer side wall respectively. When adjacent main insulation blocks are connected, the second micro positioning protrusion of the left main insulation block fits into the rocket body, and the first micro positioning protrusion of the right main insulation block presses onto the second micro positioning protrusion of the left main insulation block and engages in the corresponding second transverse engagement groove, thus achieving surface contact engagement between adjacent left and right side walls. Multiple main insulation blocks are interlocked horizontally in sequence to form a ring-shaped main insulation block layer. The annular surfaces of two adjacent main insulation blocks are also spliced ​​in a surface contact manner.

[0005] Preferably, the upper and lower sidewalls are also provided with a fourth micro-positioning boss and a third micro-positioning boss, respectively, and a vertical locking groove is formed between the micro-positioning boss and the sidewall on the same side. The micro-positioning boss on the same side and the vertical locking groove are connected to form a vertical insertion surface. The third micro-positioning boss and the fourth micro-positioning boss are not symmetrically arranged vertically and are close to the outer sidewall and the inner sidewall, respectively. When adjacent main insulation blocks are connected, the fourth micro-positioning protrusion of the lower main insulation block fits into the rocket body, and the third micro-positioning protrusion of the upper main insulation block presses against the fourth micro-positioning protrusion of the lower main insulation block and engages in the fourth vertical engagement groove of the lower main insulation block, thus achieving surface contact engagement between adjacent upper side walls. Multiple main insulation blocks are sequentially interlocked and engaged, forming a cylindrical main insulation layer.

[0006] Preferably, the splicing gap between connected main insulation blocks is ≤0.1mm; Meanwhile, the area of ​​the micro-positioning boss protruding from the grooved platform of a single main insulation block is ≤50mm². 2 This eliminates airflow disturbances caused by aerodynamic gaps and improves the anti-slip stability of pre-fixed blocks.

[0007] Preferably, after the cylindrical main insulation layer is assembled by interlocking stepped inclined platforms, toughened modified prepreg fiberglass cloth is used to reinforce and wrap the outside of the entire cylindrical main insulation layer. Furthermore, when the first layer of toughened modified prepreg fiber cloth is wrapped around the rocket body, the first layer of toughened modified prepreg fiber cloth is extended and embedded into the gap between two adjacent main insulation blocks to form a mechanical interlocking structure.

[0008] Preferably, the thickness of the main insulation block is 100mm, the groove depth is 50mm, and the depth of the first layer of toughened modified prepreg fiberglass cloth embedded in the gap between two adjacent main insulation blocks is 40mm.

[0009] Preferably, the rocket body includes a front section, a cylindrical section, and a tail section. After toughened and modified prepreg fiberglass cloth is cut according to the external dimensions of each rocket section, different reinforcement winding methods are used for different rocket sections, as detailed below: The windward side of the arrow body is toughened and modified prepreg fiberglass cloth with a 30° winding angle and 55N tension, with 3 layers, overlapping 80mm, and staggered at ±90°, and cured at 60℃ for 4 hours. The toughened modified prepreg fiberglass cloth of the column segment is wound with two layers at a 30° winding angle and 55N tension, with an overlap of 80mm, and cured at 60℃ for 4h; The tail section toughened modified prepreg fiberglass cloth is wound in two layers at a 35° winding angle and 60N tension, and cured at 60℃ for 4.5h.

[0010] Preferably, the main insulation block is a polyurethane foam block, and its main material is rigid polyurethane foam. Its raw materials include: Component A: polymeric MDI with a purity of ≥99.5% and a viscosity of 175±10 mPa·s at 25℃; Component B: polyether polyol with a hydroxyl value of 58 mg KOH / g, cyclopentane blowing agent with a closed cell rate of ≥96%, and silicone surfactant with a uniform foam control. The bonding materials between the main insulation block and the rocket body are: low-temperature adhesive and J-22 epoxy resin adhesive; The toughened modified prepreg fiber cloth is a prepreg epoxy resin fiber cloth.

[0011] Preferably, the polyurethane foam segmentation foaming mold has a structure that is a mold of corresponding size for the segmentation of the stepped inclined platform structure and the curved surface shape. The mold is made of "aerospace aluminum alloy material and 3D printed inserts" with a cavity accuracy of ±0.05mm. The mold has a built-in "micro positioning boss-groove forming core" and integrates a spiral heat conduction pipe (temperature control accuracy ±0.5℃) and a micro exhaust channel. When using the mold, the pretreatment steps are as follows: spray the inner wall with a silicone-free release agent, dry at 120℃ for 30 minutes and then cool to 45℃ to ensure that the surface is smooth and the stepped ramp structure is intact after demolding.

[0012] The above-mentioned method for preparing the segmented interlocking spliced ​​rocket body insulation layer, including the stepped inclined platform splicing and reinforcement process, comprises the following steps: S1) Shell pretreatment and gradient bonding Sandblasting cleaning: The rocket body shell is sandblasted with 80-mesh white corundum to achieve a surface roughness Ra=6~8um; then wiped with anhydrous ethanol to remove oil; Gradient adhesive application: First, apply low-temperature adhesive to the surface of the rocket body shell and cure for 12 hours until surface dry; then apply J-22 adhesive to the bonding surface of the main insulation block on the side in contact with the shell and let it dry for 5 minutes to enhance initial adhesion. S2) Interlocking splicing of stepped inclined platform Positioning and assembly: The polyurethane foam with stepped ramp structure is divided into sections and aligned with the rocket shell, so that the adjacent stepped interlocks can achieve mechanical interlocking and positioning, and can be initially fixed without additional clamps; Pressure curing: Apply radial pressure of 0.15MPa using stainless steel clamps and maintain pressure at room temperature for 2 hours to allow J-22 adhesive to fully cure; S3) Toughened modified prepreg fiberglass cloth reinforced winding High-modulus glass fiber cloth pre-impregnated with toughened modified epoxy resin is used. The epoxy resin is toughened and modified by adding a composite toughening system of carboxyl-terminated butadiene nitrile rubber and nano silica synergist. The fiber cloth has a mixed plain weave and twill weave structure. After all the polyurethane foam blocks on the outside of the rocket body are assembled, a total of 2 or 3 layers of prepreg fiberglass cloth are wrapped around them. The first layer of toughened modified prepreg fiberglass cloth embeds the continuous prepreg fiberglass cloth into the splice seam of the polyurethane foam blocks. For the stress concentration areas on the windward side of the rocket body and in the splice seams, "local densification and staggered laying" are implemented, and the fiber cloth is extended into the step groove to form mechanical interlocking, realizing the embedded anchoring design of the interlocking steps between the fiber cloth and the polyurethane foam insulation block.

[0013] Preferably, the preparation method of polyurethane foam blocks—polyurethane insulation blocks with stepped ramp structures—includes the following steps: (1) Raw material pretreatment and mixing, including the following steps: Dehydration and constant temperature: Component A and Component B are dehydrated for 2 hours each, with a moisture content ≤0.05%; then they are placed in a constant temperature chamber at 25±1℃ for 24 hours to ensure that the temperature of the two components is consistent and to improve the mixing uniformity. High-pressure mixing: Using a high-pressure foaming machine, at a pressure of 18MPa and a stirring speed of 2000r / min, components A and B are injected into the mixing chamber at a mass ratio of 1:1.2 and stirred for 8~10s to form a homogeneous emulsion slurry; (2) In-mold foaming and curing Quantitative injection: Based on the mold volume—the cavity volume including the stepped ramp structure—a micro-metering pump (accuracy ±0.5%) is used to slowly inject the mixed slurry along the inner wall of the mold. Staged foaming and curing: Foaming starts within 30 seconds at a constant temperature of 45℃ and fills the mold cavity within 4 minutes, including the fine structure of micro-positioning bosses and grooves; then the temperature is raised to 80℃ and held for 2 hours to accelerate molecular cross-linking; after natural cooling to 30℃, the mold is demolded to ensure the dimensional accuracy of the stepped ramp structure, with the width error of the micro-positioning boss ≤0.1mm; (3) Post-processing of blocks Precision testing: Use a coordinate measuring machine to test the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.1mm and the gap between the curved surface and the rocket body shell is ≤0.2mm.

[0014] Preferably, the polyurethane foam on the outer side of the rocket body is segmented and foamed using a segmented foaming process, specifically including the following: (1) Segmented foaming of the front section of the rocket body a. Mold pretreatment: Heat the mold to 45°C with heat transfer oil, keep it at that temperature for 30 minutes, spray with a silicone-free fluorocarbon release agent with a thickness of 6 μm, dry at 120°C for 30 minutes, and then cool to 45°C. b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.04 m³. 3 Inject 1.6L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming starts within 35 seconds at 45℃ and fills the cavity within 5 minutes; heat to 80℃ and hold for 2 hours, then demold after natural cooling to 30℃. d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.1mm and the gap between the arc surface and the theoretical curved surface of the front section is ≤0.2mm; (2) Segmented foaming of rocket body sections a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.03 m³. 3 Inject 1.2L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4 minutes at 45℃, demolding after heat preservation at 80℃ for 2 hours; d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.1mm and the gap between the cylindrical arc surface and the theoretical curved surface of the column segment is ≤0.2mm; (3) Segmented foaming of rocket tail section a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.035 m³. 3Inject 1.4L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4.5 minutes at 45℃, followed by demolding after holding at 80℃ for 2 hours; d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.15mm and the gap between the arc surface and the theoretical curved surface of the tail section is ≤0.2mm.

[0015] This invention provides a modular, interlocking, spliced ​​rocket body insulation layer and its preparation method. It has the following beneficial effects: The modular interlocking splicing rocket body thermal insulation layer and its preparation method of the present invention have the following advantages: To address the curved profile and aerodynamic load requirements of the rocket body, a stepped inclined platform interlocking splicing structure was designed. This structure enables surface contact splicing between rigid polyurethane foam blocks. Simultaneously, micro-positioning bosses and grooves are set on the interlocking surfaces of the steps. This not only eliminates airflow disturbances caused by aerodynamic gaps but also enhances the anti-slip stability of the pre-fixed blocks through "surface contact + positioning interlocking." This provides a ±0.05mm-level assembly benchmark for the subsequent overall covering process, solving the problems of easy loosening and large benchmark deviation in traditional stepped splicing.

[0016] A composite toughening system using toughened modified epoxy resin pre-impregnated high-modulus glass fiber cloth was adopted for toughening modification. "Local densification + staggered laying" was implemented for stress concentration areas such as the windward side of the rocket body and splice seams. Through the embedded anchoring design of interlocking steps between the fiber cloth and polyurethane foam insulation blocks, the vibration attenuation rate of the structure was increased by ≥35% and the impact strength was increased by ≥40% while controlling the overall weight increase to ≤5%.

[0017] 1. Seamless splicing, eliminating thermal bridging effect: The stepped inclined interlocking structure ensures that the splicing gap between sections is ≤0.1mm. Combined with gradient bonding and fiber reinforcement layers, the thermal bridge heat flux density is significantly reduced. After a thermal cycling test from -180℃ to 500℃, there was no gap expansion or debonding at the splicing points, and the thermal insulation performance degradation rate was <2%.

[0018] 2. Significantly improved structural mechanical performance: The interlocking stepped inclined platform provides mechanical shear resistance. Combined with the glass fiber reinforcement layer, the overall compressive strength of the insulation layer is improved, and it can withstand 15g acceleration impact and 10~2000HZ vibration. The overall insulation layer is free from cracking and delamination.

[0019] 3. Superior modular adaptability and process efficiency: Customized molds ensure precise molding, with a gap of ≤0.2mm between the polyurethane modules and the rocket body shell, eliminating a large number of subsequent cutting processes, significantly shortening the assembly cycle, improving the consistency of thermal insulation performance, and reducing raw material costs.

[0020] 4. Balancing lightweight design with efficient space utilization: The overall density of the polyurethane blocks with stepped ramps is much lighter than that of aluminum silicate cotton and cork chips; in addition, the stepped ramp structure does not take up extra internal space. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the installation of the segmented interlocking spliced ​​rocket body insulation layer of the present invention on the rocket body; Figure 2 for Figure 1 Schematic diagram of the main body insulation module structure; Figure 3 This is a schematic diagram of the installation and plugging structure of the segmented interlocking splicing rocket body insulation layer of the present invention; Figure 4 This is a schematic diagram of the structure of the first layer of toughened modified prepreg fiber cloth embedded in the gap between two adjacent main insulation blocks of the present invention.

[0022] In the figure: 1. Inner wall, 2. Outer wall, 3. Left side wall, 4. Right side wall, 5. Upper side wall, 6. Lower side wall, 7. First micro positioning boss, 8. Second micro positioning boss, 9. Lateral snap-fit ​​groove, 10. Rocket body, 11. Toughened modified prepreg fiberglass cloth, 12. Low temperature adhesive. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example 1

[0025] Please see Figure 1-4 The present invention provides a technical solution: The present invention provides a segmented interlocking splicing type rocket body insulation layer. The rocket body 10 insulation layer is a cylindrical insulation structure layer that matches the outer wall 2 of the rocket body 10 by splicing the main insulation segmented interlocking splicing structure. The segmented interlocking splicing structure adopts a stepped inclined platform interlocking splicing structure, so that the main insulation segments form a surface contact splicing - stepped interlocking surface.

[0026] The main insulation block has a hexahedral structure, including an inner wall 1, an outer wall 2, a left wall 3, a right wall 4, an upper wall 5, and a lower wall 6. The inner wall 1 and the outer wall 2 are arc surfaces that match the outer wall 2 of the rocket body 10. The left wall 3 and the right wall 4 are respectively provided with a first micro positioning boss 7 and a second micro positioning boss 8. The micro positioning boss and the side wall on the same side form a transverse snap-fit ​​groove 9. The micro positioning boss on the same side and the transverse snap-fit ​​groove 9 are connected to form a transverse insertion surface. The first micro positioning boss 7 and the second micro positioning boss 8 are not symmetrically arranged and are close to the inner wall 1 and the outer wall 2 respectively.

[0027] When adjacent main insulation blocks are connected, the second micro positioning protrusion 8 of the left main insulation block is attached to the rocket body 10, and the first micro positioning protrusion 7 of the right main insulation block is pressed onto the second micro positioning protrusion 8 of the left main insulation block and is locked in the corresponding second transverse locking groove 9, so as to realize the surface contact locking between adjacent left and right side walls. Multiple main insulation blocks are interlocked horizontally to form a ring-shaped main insulation block layer. The annular surfaces of two adjacent main insulation blocks are also spliced ​​in a surface-contact manner. The upper sidewall 5 and lower sidewall 6 of the main insulation block are also provided with a fourth micro positioning boss and a third micro positioning boss, respectively. The micro positioning boss and the sidewall on the same side form a vertical snap-fit ​​groove. The micro positioning boss on the same side and the vertical snap-fit ​​groove are connected to form a vertical insertion surface. The third micro positioning boss and the fourth micro positioning boss are not symmetrically arranged vertically and are close to the outer sidewall 2 and the inner sidewall 1, respectively.

[0028] When adjacent main insulation blocks are connected, the fourth micro positioning boss of the lower main insulation block fits into the rocket body 10, and the third micro positioning boss of the upper main insulation block presses onto the fourth micro positioning boss of the lower main insulation block and engages in the fourth vertical engagement groove of the lower main insulation block, thus achieving surface contact engagement between adjacent upper side walls. Multiple main insulation blocks are sequentially interlocked and engaged, forming a cylindrical main insulation layer.

[0029] Specifically, the splicing gap between connected main insulation modules is ≤0.1mm; simultaneously, the area of ​​the micro positioning boss protruding from the groove surface of a single main insulation module is ≤50mm². 2 This eliminates airflow disturbances caused by aerodynamic gaps and improves the anti-slip stability of pre-fixed blocks.

[0030] like Figure 4As shown, the segmented interlocking splicing rocket body insulation layer of the present invention, after being interlocked into a cylindrical main insulation layer by a stepped inclined platform, is reinforced by wrapping toughened modified prepreg fiber cloth 11 around the outside of the entire cylindrical main insulation layer. Furthermore, when wrapping the first layer of toughened modified prepreg fiber cloth 11 around the rocket body 10, the first layer of toughened modified prepreg fiber cloth 11 extends and embeds into the gaps between adjacent main insulation segments to form a mechanical interlocking structure.

[0031] The thickness of the main insulation block is 100mm, the groove depth is 50mm, and the first layer of toughened modified prepreg fiberglass cloth 11 is embedded to a depth of 40mm in the gap between two adjacent main insulation blocks. This invention's segmented interlocking splicing rocket body insulation layer, designed to meet the curved contour and aerodynamic load requirements of the rocket body 10, features a stepped inclined platform interlocking splicing structure. This allows for surface contact splicing between rigid polyurethane foam blocks, with a splicing gap ≤0.1mm. Simultaneously, micro-positioning bosses and grooves are set on the stepped interlocking surface, eliminating airflow disturbance caused by aerodynamic gaps and improving the anti-slip stability of the pre-fixed blocks through "surface contact + positioning interlocking." This provides a ±0.05mm level assembly benchmark for subsequent overall wrapping processes, solving the problems of easy loosening and large benchmark deviation in traditional stepped splicing.

[0032] Meanwhile, high-modulus glass fiber cloth pre-impregnated with toughened modified epoxy resin is used. The epoxy resin is toughened and modified by adding a composite toughening system of "terminated carboxyl butadiene nitrile rubber and nano silica synergist". The fiber cloth is a mixed plain weave and twill weave. For stress concentration areas such as the windward side of the rocket body and splice seams, "local densification and staggered laying" are implemented. Through the embedded anchoring design of interlocking steps between the fiber cloth and polyurethane foam insulation blocks, the fiber cloth extends into the groove of the step to form a mechanical interlock. Under the premise of controlling the overall weight increase to ≤5%, the vibration resistance attenuation rate of the structure is increased by ≥35% and the impact resistance is increased by ≥40%. At the same time, the delamination failure of the "foam-fiber cloth" interface at the splice is suppressed, realizing the synergistic optimization of "lightweighting-vibration resistance-impact resistance-interface stability". Example 2

[0033] The modular interlocking splicing rocket body insulation layer provided by this invention comprises a rocket body 10 including a front section, a column section, and a tail section. Toughened modified pre-impregnated fiberglass cloth 11 is cut according to the dimensional requirements of each rocket section, and different reinforcement winding methods are used for different sections, as detailed below: The windward side of the arrow body is toughened and modified prepreg fiberglass cloth 11 is wrapped with 3 layers at a 30° winding angle and 55N tension, with an overlap of 80mm, ±90° staggered, and cured at 60℃ for 4h. The column segment toughened modified prepreg fiberglass cloth 11 is wound with 2 layers at a 30° winding angle and 55N tension, with an overlap of 80mm, and cured at 60℃ for 4h; The tail section toughened modified prepreg fiberglass cloth 11 is wound in 2 layers at a 35° winding angle and 60N tension, and cured at 60℃ for 4.5h.

[0034] The main insulation block is a polyurethane foam block, and its main material is component A: polymeric MDI with a purity of ≥99.5% and a viscosity of 175±10 mPa·s at 25℃; component B: polyether polyol with a hydroxyl value of 58 mg KOH / g, cyclopentane blowing agent with a closed-cell rate of ≥96%, and silicone surfactant with a foam control and uniformity; the bonding material between the main insulation block and the rocket body 10 is low-temperature adhesive 12 and J-22 epoxy resin adhesive; the toughened modified prepreg fiberglass cloth 11 is prepreg epoxy resin fiberglass cloth. Example 3

[0035] The present invention provides a method for preparing a segmented interlocking spliced ​​rocket body insulation layer, wherein the method for preparing polyurethane foam segments—polyurethane insulation blocks with stepped ramp structures—includes the following steps: (1) Mold design and processing First, the polyurethane foam segmentation molding die has a structure consisting of a stepped ramp structure for segmentation and corresponding sized molds divided into curved shapes. The mold is made of a combination of "aviation aluminum alloy material and 3D printed inserts", with a cavity accuracy of ±0.05mm. The mold has a built-in "micro positioning boss-groove forming core" and integrates a spiral heat pipe (temperature control accuracy ±0.5℃) and a micro exhaust channel. When using the mold, the pretreatment steps are as follows: spray the inner wall with a silicone-free release agent, dry at 120℃ for 30 minutes and then cool to 45℃ to ensure that the surface is smooth and the stepped ramp structure is intact after demolding.

[0036] (2) Raw material pretreatment and mixing, including the following steps: Component A: Polymerized MDI with a purity ≥ 99.5%, viscosity at 25℃ 175 ± 10 mPa·s; Component B: Polyether polyol – hydroxyl value 58 mg KOH / g, cyclopentane blowing agent – ​​7 wt%, closed cell rate ≥ 96%, and silicone surfactant – 1.5 wt%, for uniform foam control; Dehydration and constant temperature: Component A and Component B are dehydrated for 2 hours each, with a moisture content ≤0.05%; then they are placed in a constant temperature chamber at 25±1℃ for 24 hours to ensure that the temperature of the two components is consistent and to improve the mixing uniformity. High-pressure mixing: Using a high-pressure foaming machine at a pressure of 18MPa and a stirring speed of 2000r / min, components A and B are injected into the mixing chamber at a mass ratio of 1:1.2 and stirred for 8~10s to form a homogeneous emulsion slurry; (3) In-mold foaming and curing Quantitative injection: Based on the mold volume—the cavity volume including the stepped ramp structure—a micro-metering pump (accuracy ±0.5%) is used to slowly inject the mixed slurry along the inner wall of the mold. Staged foaming and curing: Foaming starts within 30 seconds at a constant temperature of 45℃ and fills the mold cavity within 4 minutes, including the fine structure of micro-positioning bosses and grooves; then the temperature is raised to 80℃ and held for 2 hours to accelerate molecular cross-linking; after natural cooling to 30℃, the mold is demolded to ensure the dimensional accuracy of the stepped ramp structure, with the width error of the micro-positioning boss ≤0.1mm; (4) Post-processing of blocks Precision testing: Use a coordinate measuring machine to test the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.1mm and the gap between the curved surface and the rocket body shell 10 is ≤0.2mm.

[0037] The polyurethane foam on the outer side of the rocket body 10 is segmented and uses a segmented foaming process, specifically including the following: (1) The rocket body is foamed in sections at the front 10. a. Mold pretreatment: Heat the mold to 45°C with heat transfer oil, keep it at that temperature for 30 minutes, spray a 6µm thick layer of silicone-free fluorocarbon release agent, dry at 120°C for 30 minutes, and then cool to 45°C. b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.04 m³. 3 Inject 1.6L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming starts within 35 seconds at 45℃ and fills the cavity within 5 minutes; heat to 80℃ and hold for 2 hours, then demold after natural cooling to 30℃. d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.1mm and the gap between the arc surface and the theoretical curved surface of the front section is ≤0.2mm; (2) The rocket body is foamed in 10 sections. a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.03 m³. 3 Inject 1.2L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4 minutes at 45℃, demolding after heat preservation at 80℃ for 2 hours; d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam, and ensure that the gap between the micro positioning boss and the groove is ≤0.1mm, and the gap between the cylindrical arc surface and the theoretical curved surface of the column segment is ≤0.2mm.

[0038] (3) The tail section of the rocket body is foamed in sections. a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.035 m³. 3 Inject 1.4L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4.5 minutes at 45℃, followed by demolding after holding at 80℃ for 2 hours; d. Post-processing: Use a coordinate measuring machine to check the dimensions of the stepped ramp and the curvature of the surface of the segmented polyurethane foam to ensure that the gap between the micro positioning boss and the groove is ≤0.15mm and the gap between the arc surface and the theoretical curved surface of the tail section is ≤0.2mm. Example 4

[0039] The method for preparing the segmented interlocking spliced ​​rocket body thermal insulation layer of the present invention, including the stepped inclined platform splicing and reinforcement process, comprises the following steps: S1) Shell pretreatment and gradient bonding Sandblasting cleaning: The shell of rocket body 10 is sandblasted with 80-mesh white corundum, with a surface roughness Ra=6~8um; then wiped with anhydrous ethanol to remove oil; Gradient adhesive application: First, apply low-temperature adhesive 12 to the surface of the rocket body 10 shell and cure for 12 hours until surface dry; then apply J-22 adhesive to the bonding surface of the main insulation block on the side in contact with the shell and let it dry for 5 minutes to enhance initial adhesion. S2) Interlocking splicing of stepped inclined platform Positioning and assembly: The polyurethane foam with stepped ramp structure is divided into sections and aligned with the rocket shell, so that the adjacent stepped interlocks can achieve mechanical interlocking and positioning, and can be initially fixed without additional clamps; Pressure curing: Apply radial pressure of 0.15MPa using stainless steel clamps and maintain pressure at room temperature for 2 hours to allow J-22 adhesive to fully cure; S3) Toughened modified prepreg fiberglass cloth 11 reinforced winding High-modulus glass fiber cloth pre-impregnated with toughened modified epoxy resin is used. The epoxy resin is toughened and modified by adding a composite toughening system of "terminated carboxyl butadiene nitrile rubber and nano silica synergist". The fiber cloth has a mixed plain weave and twill weave structure. After all the polyurethane foam blocks on the outside of the rocket body 10 are assembled, a total of 2 or 3 layers of prepreg fiberglass cloth are wrapped around them. The first layer of toughened modified prepreg fiberglass cloth 11 embeds the continuous prepreg fiberglass cloth into the splice seam of the polyurethane foam blocks. For the stress concentration areas on the windward side and splicing seams of the rocket body 10, "local densification and staggered laying" are implemented, and the fiber cloth is extended into the step groove to form mechanical interlocking, realizing the embedded anchoring design of the interlocking steps between the fiber cloth and the polyurethane foam insulation block.

[0040] The performance verification results of the segmented interlocking spliced ​​rocket body insulation layer of the present invention prepared above are as follows: 1. Thermal insulation performance: The thermal conductivity of the insulation layer is 0.022 W / (m·K), and the attenuation rate is <5% after 100 cycles of heating and cooling from -180℃ to 500℃.

[0041] 2. Mechanical properties: Compressive strength ≥1.7MPa; after 15g impact and 10~2000HZ vibration, the blocks do not crack or debond.

[0042] 3. Splicing effect: The gap at the joint of polyurethane foam blocks is ≤0.65mm, and the thermal bridge temperature difference is ≤1.2℃.

[0043] The above data results prove that this embodiment achieves efficient preparation and reliable performance of the insulation layer of the rocket body's front section, column section, and tail section through "segmented customized block + precise foaming + stepped inclined platform interlocking + fiber reinforcement", solving the problems of "poor adaptability, low reliability, and inconsistent processes" of traditional solutions.

[0044] In summary, this invention provides a rocket body insulation layer solution consisting of "segmented polyurethane foam with stepped inclined platform interlocking structure + gradient bonding + integrated reinforcement". It achieves precise foaming of complex segments through customized molds, and effectively solves the problems of "heat leakage during splicing, weak structure and poor compatibility" of traditional insulation materials by combining stepped inclined platform splicing and reinforcement processes.

[0045] The above are merely embodiments of the present invention. For example, after all the polyurethane foam blocks on the outside of the rocket body 10 are assembled, two or three layers of pre-impregnated fiberglass cloth are then wrapped around them to realize the segmented interlocking splicing rocket body insulation layer and its preparation method of the present invention.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A modular, interlocking, spliced ​​rocket body insulation layer, characterized in that, The insulation layer of the rocket body (10) is a cylindrical insulation structure layer that matches the outer wall (2) of the rocket body (10) by splicing the main insulation blocks into an interlocking splicing structure. The segmented interlocking splicing structure adopts a stepped inclined platform interlocking splicing structure, so that the main insulation segments form a surface contact splicing - stepped interlocking surface. The main insulation block has a hexahedral structure, including an inner sidewall (1), an outer sidewall (2), a left sidewall (3), a right sidewall (4), an upper sidewall (5), and a lower sidewall (6). Its inner wall (1) and outer wall (2) are arc surfaces that match the outer wall (2) of the rocket body (10). The left side wall (3) and the right side wall (4) are respectively provided with a first micro positioning boss (7) and a second micro positioning boss (8), and the micro positioning boss and the side wall on the same side form a transverse snap-fit ​​groove (9). The micro positioning boss on the same side and the transverse snap-fit ​​groove (9) are connected to form a transverse insertion surface. The first micro positioning boss (7) and the second micro positioning boss (8) are not symmetrically arranged and are close to the inner side wall (1) and the outer side wall (2) respectively. When the adjacent main insulation blocks are connected, the second micro positioning protrusion (8) of the left main insulation block is attached to the rocket body (10), and the first micro positioning protrusion (7) of the right main insulation block is pressed onto the second micro positioning protrusion (8) of the left main insulation block and is locked in the corresponding second transverse locking groove (9), so as to realize the surface contact locking between the adjacent left and right side walls. Multiple main insulation blocks are interlocked and locked in the transverse left and right to form a ring-shaped main insulation block layer. The annular surfaces of two adjacent main insulation blocks are also spliced ​​in a surface contact manner.

2. The segmented interlocking splicing type rocket body insulation layer according to claim 1, characterized in that, The upper sidewall (5) and lower sidewall (6) are also provided with a fourth micro positioning boss and a third micro positioning boss respectively. The micro positioning boss and the sidewall on the same side form a vertical snap-fit ​​groove. The micro positioning boss on the same side and the vertical snap-fit ​​groove are connected to form a vertical insertion surface. The third micro positioning boss and the fourth micro positioning boss are not symmetrically arranged up and down and are close to the outer sidewall (2) and the inner sidewall (1) respectively. When adjacent main insulation blocks are connected, the fourth micro positioning boss of the lower main insulation block is attached to the rocket body (10), and the third micro positioning boss of the upper main insulation block is pressed onto the fourth micro positioning boss of the lower main insulation block and locked in the fourth vertical locking groove of the lower main insulation block, so as to realize the surface contact locking between adjacent upper side walls. Multiple main insulation blocks are interlocked and locked in sequence to form a cylindrical main insulation layer.

3. The segmented interlocking splicing type rocket body insulation layer according to claim 1, characterized in that, The joint gap between the connected main insulation blocks is ≤0.1mm; Meanwhile, the area of ​​the micro-positioning boss protruding from the grooved platform of a single main insulation block is ≤50mm². 2 .

4. The segmented interlocking splicing type rocket body insulation layer according to claim 3, characterized in that, After the tubular main insulation layer is spliced ​​together by interlocking stepped inclined platforms, toughened modified prepreg glass fiber cloth (11) is used to reinforce and wrap the outside of the entire tubular main insulation layer. Furthermore, when the first layer of toughened modified prepreg fiber cloth (11) is wrapped around the rocket body (10), the first layer of toughened modified prepreg fiber cloth (11) is extended and embedded into the gap between the two adjacent main insulation blocks to form a mechanical interlocking structure.

5. The segmented interlocking splicing type rocket body insulation layer according to claim 3, characterized in that, The thickness of the main insulation block is 100mm, the groove depth is 50mm, and the first layer of toughened modified prepreg glass fiber cloth (11) is embedded into the gap between two adjacent main insulation blocks to a depth of 40mm.

6. The segmented interlocking splicing type rocket body insulation layer according to claim 4, characterized in that, The rocket body (10) includes a front section, a column section, and a tail section. After toughened modified prepreg fiberglass cloth (11) is cut according to the external dimensions of each rocket section, different reinforcement winding methods are used for different rocket sections, as follows: The windward side of the arrow body is toughened and modified prepreg fiberglass cloth (11) wrapped with 3 layers at a 30° winding angle and 55N tension, with an overlap of 80mm, ±90° staggered, and cured at 60℃ for 4h. The column segment toughened modified prepreg fiberglass cloth (11) is wound with 2 layers at a 30° winding angle and 55N tension, with an overlap of 80mm, and cured at 60℃ for 4h; The tail section toughened modified prepreg fiberglass cloth (11) is wound in 2 layers with a 35° winding angle and 60N tension, and cured at 60°C for 4.5h.

7. The segmented interlocking splicing type rocket body insulation layer according to claim 5, characterized in that, The main insulation block is a polyurethane foam block, and its main material is rigid polyurethane foam. Its raw materials include: Component A: polymeric MDI with a purity of ≥99.5% and a viscosity of 175±10 mPa·s at 25℃; Component B: polyether polyol with a hydroxyl value of 58 mg KOH / g, cyclopentane blowing agent with a closed cell rate of ≥96%, and silicone surfactant with a foam control and uniformity. The bonding materials between the main thermal insulation block and the rocket body (10) are: low temperature adhesive (12) and J-22 epoxy resin adhesive; The toughened modified prepreg fiber cloth (11) is a prepreg epoxy resin fiber cloth.

8. The segmented interlocking splicing type rocket body insulation layer according to claim 7, characterized in that, The polyurethane foam segmentation foaming mold is structured as a mold of corresponding size for the stepped inclined platform structure and curved surface division of the segmentation. It is made of "aerospace aluminum alloy material and 3D printed inserts" and the cavity accuracy reaches ±0.05mm. The mold has a built-in "micro positioning boss-groove forming core" and integrates a spiral heat conduction pipe and micro exhaust groove. When using the mold, the pretreatment steps are as follows: spray the inner wall with a silicone-free release agent, dry at 120℃ for 30 minutes and then cool to 45℃ to ensure that the surface is smooth and the stepped ramp structure is intact after demolding.

9. The method for preparing a segmented interlocking spliced ​​rocket body thermal insulation layer according to claim 7, characterized in that, The stepped inclined platform splicing and reinforcement process includes the following steps: S1) Shell pretreatment and gradient bonding Sandblasting cleaning: The shell of the rocket body (10) is sandblasted with 80-mesh white corundum, with a surface roughness Ra=6~8um; then wiped with anhydrous ethanol to remove oil; Gradient adhesive application: First, apply low-temperature adhesive (12) to the surface of the rocket body (10) and cure for 12 hours until surface dry; then apply J-22 adhesive to the bonding surface of the main insulation block on the side in contact with the shell and let it dry for 5 minutes to enhance the initial adhesion. S2) Interlocking splicing of stepped inclined platform Positioning and assembly: The polyurethane foam with stepped ramp structure is divided into sections and aligned with the rocket shell, so that the adjacent stepped interlocks can achieve mechanical interlocking and positioning. Pressure curing: Apply radial pressure of 0.15MPa using stainless steel clamps and maintain pressure at room temperature for 2 hours to allow J-22 adhesive to fully cure; S3) Toughened modified prepreg fiber cloth (11) reinforced winding High-modulus glass fiber cloth pre-impregnated with toughened modified epoxy resin is used. The epoxy resin is toughened and modified by adding a composite toughening system of "terminated carboxyl butadiene nitrile rubber and nano silica. The fiber cloth has a mixed plain weave and twill weave structure. After all the polyurethane foam blocks on the outside of the rocket body (10) are assembled, two or three layers of prepreg fiberglass cloth are wrapped around them. The first layer of toughened modified prepreg fiberglass cloth (11) embeds the continuous prepreg fiberglass cloth into the splice seam of the polyurethane foam blocks. For the stress concentration areas on the windward side and splice seams of the rocket body (10), "local densification and staggered laying" are implemented, and the fiber cloth is extended into the step groove to form mechanical interlocking, realizing the embedded anchoring design of the interlocking step between the fiber cloth and the polyurethane foam insulation block.

10. The method for preparing a segmented interlocking spliced ​​rocket body thermal insulation layer according to claim 9, characterized in that, The preparation method of polyurethane foam blocks—polyurethane insulation blocks with stepped ramp structures—includes the following steps: (1) Raw material pretreatment and mixing, including the following steps: Dehydration and constant temperature: Component A and Component B are dehydrated for 2 hours each, with a moisture content ≤0.05%; then they are placed in a constant temperature chamber at 25±1℃ for 24 hours to ensure that the temperature of the two components is consistent and to improve the mixing uniformity. High-pressure mixing: Using a high-pressure foaming machine at a pressure of 18MPa and a stirring speed of 2000r / min, components A and B are injected into the mixing chamber at a mass ratio of 1:1.2 and stirred for 8~10s to form a homogeneous emulsion slurry; (2) In-mold foaming and curing Quantitative injection: Based on the mold volume—the cavity volume including the stepped ramp structure—a micro metering pump is used to slowly inject the mixed slurry along the inner wall of the mold; Staged foaming and curing: Foaming starts within 30 seconds at a constant temperature of 45℃ and fills the mold cavity within 4 minutes, including the fine structure of micro-positioning bosses and grooves; then the temperature is raised to 80℃ and held for 2 hours to accelerate molecular cross-linking; after natural cooling to 30℃, the mold is demolded to ensure the dimensional accuracy of the stepped ramp structure, with the width error of the micro-positioning boss ≤0.1mm; The polyurethane foam on the outside of the rocket body (10) is segmented and foamed using a segmented foaming process, specifically including the following: (1) The front section of the rocket body (10) is segmented and foamed. a. Mold pretreatment: Heat the mold to 45°C with heat transfer oil, keep it at that temperature for 30 minutes, spray with a silicone-free fluorocarbon release agent with a thickness of 6 μm, dry at 120°C for 30 minutes, and then cool to 45°C. b. Raw material mixing and injection: A high-pressure foaming machine is used to mix components A and B at a mass ratio of 1:1.2 at 18 MPa pressure and 2000 r / min speed, stirring for 10 seconds to form a homogeneous slurry; the cavity volume of a single mold is 0.04 m³. 3 Inject 1.6L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming starts within 35 seconds at 45℃ and fills the cavity within 5 minutes; heat to 80℃ and hold for 2 hours, then demold after natural cooling to 30℃. (2) Rocket body (10) segmented foaming a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: The homogeneous slurry is the same as that in the previous stage; The cavity volume of a single mold piece is 0.03m³. 3 Inject 1.2L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4 minutes at 45℃, demolding after heat preservation at 80℃ for 2 hours; (3) Rocket body (10) tail section segmented foaming a. Mold pretreatment: Same as the previous step; b. Raw material mixing and injection: The homogeneous slurry is the same as that in the previous stage; The cavity volume of a single mold piece is 0.035m³. 3 Inject 1.4L of mixed slurry slowly along the curved wall of the mold; c. Foaming and curing: Foaming within 4.5 minutes at 45℃, followed by demolding after holding at 80℃ for 2 hours.

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