Aramid honeycomb sandwich structure rocket fairing shell, forming mold and forming method thereof

Abstract

The invention discloses an aramid honeycomb sandwich structure rocket fairing shell, a forming mold and a forming method thereof, comprising a fairing shell, wherein the front end of the fairing shell is a conical section, and the middle and rear ends are cylindrical sections. In the invention, the first stretching length of the white honeycomb is not limited by the honeycomb cells, the number of layers of aramid paper can be determined according to the length of the fairing shell, and the preparation is performed using a standard honeycomb stretching machine and a dipping tank, which saves costs, and the honeycomb core of the fairing shell does not need to be spliced ​​in multiple pieces, thereby avoiding the weak link of the splicing interface and improving the overall quality. Small holes are evenly distributed on the female mold and male mold forming mold surfaces of the honeycomb shaping mold. When the honeycomb core is solidified, a controlled airflow is connected, and the upward airflow thrust received by the molten phenolic resin on the honeycomb hole wall is equivalent to the gravity of the resin flowing downward, and the phenolic resin remains in situ solidified, avoiding the blockage of the honeycomb bottom, and ensuring the density uniformity in the honeycomb thickness direction.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace vehicle manufacturing, and in particular to an aramid honeycomb sandwich structure rocket fairing shell, a molding die and a molding method thereof. Background Art

[0002] The rocket fairing is located on the top of the launch vehicle. It plays an important role in reducing air resistance and protecting the payload during the rocket's passage through the atmosphere. The rocket fairing shell is the main component of the fairing, and its lightweight is of great significance. Under the same thrust, it can carry a heavier payload and reduce the launch cost. At present, the aramid honeycomb sandwich structure rocket fairing shell is an advanced lightweight design. It minimizes weight while ensuring structural strength. Due to its high specific strength and specific stiffness, it can maintain good stability when subjected to complex loads such as aerodynamics and vibration during the launch process. The honeycomb sandwich structure has good thermal insulation properties. The hexagonal honeycomb cells form small thermal insulation spaces, which have a good effect on reducing the transfer of external heat into the interior.

[0003] In terms of manufacturing process, the area of ​​the rocket fairing shell is large, and it is necessary to precisely co-cure and composite the honeycomb core and composite panel of equal thickness. The rocket fairing is a two-half structure, and the shape includes a conical section and a cylindrical section, with a large curvature and a high design thickness. It is formed by using conventional large pieces of aramid honeycomb sheets of equal thickness, and the honeycomb core is difficult to bend and fit the mold surface of the molding mold. Using increased pressure molding will cause the outer side of the curved surface of the honeycomb core to crack and the inner side to collapse.

[0004] The compression strength of aramid honeycomb is determined by the glue content of aramid paper, that is, by the density of honeycomb. The conical section at the front end of the rocket fairing shell is under greater pressure than the cylindrical section at the middle and rear end, and the honeycomb core at the front end requires a higher density. The current honeycomb sheet can only provide materials with uniform density. To achieve variable density of the honeycomb core of the rocket fairing shell, only two honeycomb sheets of different densities can be used for splicing. The connection interface of this splicing will become a weak link, causing stress concentration and construction difficulty. The strong vibration of flight will cause the connection interface to loosen and crack. At the same time, it affects the thermal insulation, wave transmission and other properties. Using high-density honeycombs will increase the overall weight and is not conducive to lightweighting.

[0005] As the fairing structure becomes larger and larger, the conventional aramid honeycomb preparation method has limited the implementation of the integral molding process of the rocket fairing shell. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art, and to propose an aramid honeycomb sandwich structure rocket fairing shell, a molding mold and a molding method thereof, so as to achieve precise bonding and gluing of the inner surface of the outer panel of the fairing shell with the outer surface of the conformal aramid honeycomb core. After the inner panel prepreg is laid on the inner surface of the honeycomb core, the autoclave process is used to achieve the overall co-curing molding of the rocket fairing shell.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A rocket fairing shell with an aramid honeycomb sandwich structure comprises a fairing shell, the front end of the fairing shell is a conical section, the middle and rear ends are cylindrical sections, and the fairing shell is a co-cured one-piece molding structure composed of a shell outer panel, a shell inner panel and a honeycomb core located therebetween.

[0008] Preferably, the honeycomb core includes a honeycomb high-density area, a honeycomb low-density area and a honeycomb chamfer area in sequence from the front end to the rear end.

[0009] Preferably, the honeycomb core is formed by stretching and curing a white honeycomb, and stretch fabric strips are glued to the upper and lower surfaces of the laminated straight strips of the white honeycomb, and the stretch fabric strips are provided with evenly distributed stretch fabric rings.

[0010] A honeycomb core forming mold comprises a honeycomb shaping mold female mold, a honeycomb shaping mold male mold and a guide locking structure. The honeycomb shaping mold female mold and the honeycomb shaping mold male mold are molded and fixed through the guide locking structure.

[0011] Preferably, the female mold of the honeycomb shaping mold is provided with a concave female mold forming mold surface, the female mold forming mold surface is evenly distributed with female mold small-diameter through holes, the female mold of the honeycomb shaping mold is a hollow structure, the side wall of the female mold of the honeycomb shaping mold is installed with a quick-connect air nozzle, and a hook is provided at the edge of the recess of the female mold of the honeycomb shaping mold.

[0012] Preferably, the honeycomb shaping mold male mold is provided with a raised male mold forming surface cooperating with the female mold forming surface, the male mold forming surface is evenly distributed with male mold small-diameter through holes, the honeycomb shaping mold male mold is a hollow structure, and its end face is provided with a plurality of end face hollow holes, and hook avoidance grooves are symmetrically provided on both sides of the female mold forming surface.

[0013] Preferably, the guide locking structure includes a guide column and a locking screw hole arranged on the female mold of the honeycomb shaping mold, and a guide sleeve and a bolt through hole arranged on the male mold of the honeycomb shaping mold. The guide column and the guide sleeve cooperate with each other, and a locking bolt is inserted in the bolt through hole, and the locking bolt is threadedly connected to the locking screw hole.

[0014] A method for forming a honeycomb core using a honeycomb core forming mold, the method comprising the following steps: Step 1: Preparation of high-thickness laminated straight strips: The length of the glue-coated aramid paper and the number of staggered stacking layers are set according to the L-direction and W-direction dimensions of the honeycomb core, and the edge processing allowance is reserved. After the stacking is solidified, the width of the stacking strips is set according to the thickness of the honeycomb core for cutting, and the stretching strips are glued to the upper and lower surfaces of the stacking strips, and the stretching strips are provided with evenly distributed stretching cloth rings; Step 2: First stretching and dipping of white honeycomb: The laminated straight strips are stretched into a white honeycomb with incompletely expanded cells, the length of the white honeycomb is suitable for the stretched cloth ring to be fixed on the hook of the dipping tool, and the white honeycomb and the dipping tool are immersed in the phenolic glue pool for dipping; The phenolic resin glue is diluted with industrial alcohol to a set density; the aramid paper is impregnated with the glue by repeated dipping, airing, turning, drying, and weighing. The glue content of the white honeycomb reaches the weight requirement of the low-density area of ​​the honeycomb core, and the glue content of the aramid paper is uniform; Step 3: Second stretching of white honeycomb: The white honeycomb is moved to the honeycomb shaping mold for the second stretching, and bidirectional radial stretching is performed along the male mold forming mold surface of the honeycomb shaping mold. When the mold is in place, the cells of the white honeycomb are stretched to a regular hexagon. The mold locking bolt is screwed and locked with the mold locking screw hole through the bolt through hole; Step 4: The honeycomb core is cured and shaped for the first time: After the honeycomb shaping mold is closed, it is moved into the oven. The quick-connect air nozzle of the female mold of the honeycomb shaping mold is connected to the high-pressure air source. The airflow passes through the small-diameter through-holes of the female mold, the honeycomb grids and the small-diameter through-holes of the male mold, and finally exits the mold through the hollow holes on the end face, forming an upward airflow thrust on the honeycomb hole wall. The gas flow rate is set so that the upward thrust of the heated and melted phenolic resin on the honeycomb cell wall before solidification is equivalent to the gravity of the resin flowing downward. The phenolic resin remains solidified in place to avoid flowing to the bottom of the honeycomb to block the cells, and the density uniformity in the thickness direction of the honeycomb is ensured. After the honeycomb high temperature curing process is completed, it is cooled to room temperature, the female mold of the honeycomb shaping mold is removed, the stretching cloth ring is removed from the hooks of all the female molds of the honeycomb shaping mold, and the honeycomb core is taken out; Step 5: Increase the local density of the honeycomb core: Move the honeycomb core to the spray tooling, use a film to cover and protect the low-density area of ​​the honeycomb, and move the spray tooling to the robot spraying position for positioning; The spraying program is called, and the robot's mechanical arm drives the spray head to spray phenolic resin glue along the inner surface of the honeycomb core to increase the glue content in the high-density area of ​​the honeycomb core; The phenolic resin glue is diluted with industrial alcohol to the set density; the glue content in the high-density area of ​​the honeycomb is evenly increased to the design weight requirement by repeated spraying, drying and weighing. After drying, remove the protective film, move the honeycomb core back to the honeycomb shaping mold, put all the stretched cloth rings back on the hooks of the female mold of the honeycomb shaping mold, lock the mold, and put it into the oven; According to step 4, the honeycomb core is cured at high temperature for the second time, and after being cooled to room temperature, the positive mold of the honeycomb shaping mold is removed, and the honeycomb core is taken out; Step 6: Edge processing of honeycomb core: The honeycomb core is placed in the female mold of the fairing shell, and the designed edge of the fairing honeycomb core is marked, and the net size of the honeycomb core is cut according to the marked line. The honeycomb chamfer area is processed on the edges of the honeycomb core, and the honeycomb cells in the honeycomb chamfer area are filled with solid foam to complete the preparation of the conformal aramid honeycomb core.

[0015] A method for forming an aramid honeycomb sandwich structure rocket fairing shell, the method comprising the following steps: Step 1: Preparation of the outer panel of the shell: Carbon fiber prepreg is laid on the female mold surface of the fairing shell. After laying the designed number of layers, a vacuum bag system is laid and the shell is sent to the autoclave for high-temperature pressurization and curing. After the solidified outer shell panel cools down, it is demoulded, the excess is cut off according to the edge line, the inner surface is fully polished to the set roughness, the dust is sucked out, and it is wiped clean with a detergent; Put the outer panel of the shell back into the female mold, use high-temperature tape to position it, evenly apply a layer of primer on the inner surface, then lay a layer of high-temperature film, and apply another layer of primer on the film; Step 2: Gluing of conformable aramid honeycomb core: The preformed conformable aramid honeycomb core is conformably placed in the outer panel of the shell and positioned so that the outer surface contacts the high-temperature adhesive film. A layer of primer is evenly applied on the inner surface of the honeycomb core, and then a layer of high-temperature adhesive film is laid, and another layer of primer is applied on the adhesive film. Step 3: Laying of the panels inside the shell: A carbon fiber prepreg layer is laid on the high-temperature adhesive film on the inner surface of the honeycomb core. The prepreg in the edge area around the shell inner panel is directly in contact with the shell outer panel. After laying the designed number of layers, the prepreg of the shell inner panel completely wraps the honeycomb core. Step 4: Co-curing of the fairing shell: A high-temperature vacuum bag system is laid on the inner panel of the shell, and the system is sent into an autoclave for high-temperature pressurized co-curing and molding. After curing, the system is cooled to room temperature and the product is taken out to complete the molding of the aramid honeycomb sandwich structure rocket fairing shell.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The first stretching length of the white honeycomb is not limited by the honeycomb cells. The number of layers of aramid paper can be determined according to the length of the fairing shell. It can be prepared using a standard honeycomb stretching machine and a dip tank, which saves costs. The honeycomb core of the fairing shell does not need to be spliced ​​in multiple pieces, avoiding weak links in the splicing interface and improving the overall quality.

[0017] (2) Since the phenolic resin of the white honeycomb is not cured, it has good overall flexibility. When the high-thickness white honeycomb is bent with a large curvature in the unfolding direction and stretched radially along the arc surface, the cells can remain intact. In the connection area between the conical section and the cylindrical section of the fairing shell, the honeycomb core cells have a uniform transition.

[0018] (3) The spunbond honeycomb phenolic composite material is formed by the pressure of the honeycomb shaping mold, and then cured at high temperature. The formed honeycomb core has no bending stress and can be precisely fitted with the outer panel in a natural state. The fairing shell does not need to be formed by a separate honeycomb bonding process, which saves one process compared with the existing technology.

[0019] (4) Small holes are evenly distributed on the female and male molding surfaces of the honeycomb shaping mold. When the honeycomb core is solidifying, a controlled airflow is connected. The upward airflow thrust exerted on the molten phenolic resin on the honeycomb pore wall is equivalent to the gravity of the resin flowing downward. The phenolic resin remains solidified in situ, avoiding clogging of the honeycomb bottom and ensuring uniform density in the honeycomb thickness direction.

[0020] (5) A robotic arm is used to spray and secondary cure the local phenolic resin of the honeycomb core to increase the local density of the honeycomb core. This solves the different compression strength requirements of the conical section and cylindrical section of the fairing shell for the honeycomb core. There is no need to splice honeycomb blocks of different densities. The use of honeycombs of corresponding density can achieve the best lightweight design and improve the adaptability of the fairing when launching different payloads on a space vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more specifically and intuitively illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0022] Figure 1 2 is a schematic structural diagram of a rocket fairing shell having a spunbond honeycomb sandwich structure according to an embodiment of the present invention; Figure 2 The embodiment of the present invention Figure 1 A magnified view of the honeycomb core structure in the area marked with A; Figure 3 is an axial cross-sectional view of a cylindrical region of a rocket fairing shell according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of an incompletely stretched white honeycomb according to an embodiment of the present invention; Figure 5 Schematic diagram of the structure of the female mold of the honeycomb shaping mold according to an embodiment of the present invention; Figure 6 Schematic diagram of the structure of the male mold of the honeycomb shaping mold according to an embodiment of the present invention; Figure 7 It is a structural schematic diagram of the honeycomb core of an embodiment of the present invention completing the second stretching in the honeycomb shaping mold, and the honeycomb core is in the mold cavity for curing and shaping; Figure 8 The honeycomb shaping mold of the embodiment of the present invention is in the mold closing state. Figure 7 A schematic diagram of the cross-sectional structure of the marked cutting line B; Fig. 9 2 is a schematic structural diagram of a prefabricated high-thickness variable-density conformable aramid honeycomb core according to an embodiment of the present invention; Fig.10 The embodiment of the present invention Fig. 9 Enlarged view of the honeycomb core structure in the area marked with C in the middle.

[0023] In the figure: Fairing shell 1, conical section 101, cylindrical section 102; Shell outer panel 201, shell inner panel 202, adhesive film 203; Honeycomb core 3, honeycomb high density area 301, honeycomb low density area 302, honeycomb chamfer area 303; White honeycomb 4, stretched fabric strip 5, stretched fabric 501; Honeycomb shaping mold female mold 6, female mold forming mold surface 601, female mold small diameter through hole 602, guide column 603, locking mold screw hole 604, quick-connect air nozzle 605, hook 606 Honeycomb shaping mold male mold 7, male mold forming mold surface 701, male mold small diameter through hole 702, guide sleeve 703, bolt through hole 704, end face hollow hole 705, hook avoidance groove 706 Tighten the bolt 8. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0025] Reference Figure 1-10A rocket fairing shell with an aramid honeycomb sandwich structure includes a fairing shell 1, the front end of the fairing shell 1 is a conical section 101, the middle and rear ends are cylindrical sections 102, the fairing shell 1 is composed of a shell outer panel 201, a shell inner panel 202 and a honeycomb core 3 located therebetween to form a co-cured one-piece molding structure, the shell outer panel 201 and the shell inner panel 202 are coated with an adhesive film 201, the adhesive film 201 is used to increase the bonding strength between the honeycomb core 3 and the inner and outer panels, better transfer flight stress, and play a sealing and protective role for the fairing shell 1.

[0026] In this embodiment, the honeycomb core 3 includes a honeycomb high-density area 301 , a honeycomb low-density area 302 and a honeycomb chamfer area 303 from the front end to the rear end.

[0027] In this embodiment, the honeycomb core 3 is formed by stretching and curing a white honeycomb 4, and the white honeycomb 4 has stretched cloth strips 5 glued to the upper and lower surfaces of the laminated straight strips, and the stretched cloth strips are provided with evenly distributed stretch cloth rings 501.

[0028] A honeycomb core forming mold comprises a honeycomb shaping mold female mold 6, a honeycomb shaping mold male mold 7 and a guide locking structure. The honeycomb shaping mold female mold 6 and the honeycomb shaping mold male mold 7 are molded and fixed by the guide locking structure.

[0029] In this embodiment, a recessed female mold forming surface 601 is provided on the female mold 6 of the honeycomb shaping mold, and female mold small-diameter through holes 602 are evenly distributed on the female mold forming surface 601. The female mold 6 of the honeycomb shaping mold is a hollow structure, and a quick-connect air nozzle 605 is installed on the side wall of the female mold 6 of the honeycomb shaping mold. A hook 606 is provided at the edge of the recess of the female mold 6 of the honeycomb shaping mold.

[0030] The shape of the female mold forming surface 601 is the same as the outer surface of the fairing honeycomb core 3 , and the shape of the male mold forming surface 701 is the same as the inner surface of the fairing honeycomb core 3 .

[0031] In this embodiment, the honeycomb shaping mold male mold 7 is provided with a raised male mold molding surface 701 that cooperates with the female mold molding surface 601, and the male mold molding surface 701 is evenly distributed with male mold small-diameter through holes 702. The honeycomb shaping mold male mold 7 is a hollow structure, and its end face is provided with a plurality of end face hollow holes 705, and hook avoidance grooves 706 are symmetrically provided on both sides of the female mold molding surface 601.

[0032] In this embodiment, the guide locking structure includes a guide column 603 and a locking screw hole 604 arranged on the female mold 6 of the honeycomb shaping mold, and a guide sleeve 703 and a bolt through hole 704 arranged on the male mold 7 of the honeycomb shaping mold. The guide column 603 and the guide sleeve 703 cooperate with each other, and a locking bolt 8 is inserted into the bolt through hole 704, and the locking bolt 8 is threadedly connected to the locking screw hole 604.

[0033] The stretching cloth rings 501 at both ends of the white honeycomb 4 are all hung on the corresponding hooks 606 of the female mold 6. The male mold molding die surface 701 contacts the upper surface of the white honeycomb 4 downward, and the male mold 7 is slowly molded downward by matching the mold closing guide sleeve 703 with the mold closing guide column 603. The white honeycomb 4 is stretched for the second time under the mold closing pressure of the male mold molding die surface 701, that is, it is stretched in two directions radially along the arc-shaped die surface of the male mold 7.

[0034] When the mold is in place, the locking bolt 8 passes through the locking bolt through hole 704 and is screwed and locked with the locking screw hole 604. At this time, the cells of the white honeycomb 4 are stretched to a regular hexagon, and the honeycomb core cells are evenly transitioned in the transition area between the conical section 101 and the cylindrical section 102. The hook avoidance groove 706 set in the male mold 7 can avoid interference between the male mold molding surface 701 and the hook 606 when the mold is closed.

[0035] A method for forming a honeycomb core using a honeycomb core forming mold, the method comprising the following steps: Step 1: Preparation of high-thickness laminated straight strips: The length of the glue-coated aramid paper and the number of staggered stacking layers are set according to the L-direction and W-direction dimensions of the honeycomb core 3, and the edge processing allowance is reserved. After the stacking is solidified, the width of the stacking strips is set according to the thickness of the honeycomb core 3 for cutting, and the stretching strips 5 are glued to the upper and lower surfaces of the stacking strips, and the stretching strips are provided with evenly distributed stretching cloth rings 501; Step 2: First stretching and dipping of white honeycomb 4: The laminated straight strips are stretched into a white honeycomb 4 whose cells are not fully expanded, and the length of the white honeycomb 4 is suitable for the stretching cloth ring 501 to be fixed on the hook 606 of the dipping tool, and the white honeycomb 4 and the dipping tool are immersed in the phenolic glue pool for dipping; The phenolic resin glue is diluted to a set density using industrial alcohol; the aramid paper is impregnated with the glue by repeated dipping, airing, turning, drying, and weighing, so that the glue content of the white honeycomb 4 reaches the weight requirement of the honeycomb low-density area 302 of the honeycomb core 3, and the aramid paper has a uniform glue content; Step 3: Second stretching of white honeycomb 4: The white honeycomb 4 is moved to the honeycomb shaping mold for the second stretching, and is subjected to bidirectional radial stretching along the male mold forming mold surface 701 of the male mold 7 of the honeycomb shaping mold. When the mold is in place, the cells of the white honeycomb 4 are stretched to a regular hexagon. The mold locking bolt 8 is screwed and locked with the mold locking screw hole 604 through the bolt through hole 704; Step 4: The honeycomb core 3 is cured and shaped for the first time: After the honeycomb shaping mold is closed, it is moved into the oven. The quick-connect air nozzle 605 of the female mold 6 of the honeycomb shaping mold is connected to the high-pressure air source. The airflow passes through the small-diameter through hole 602 of the female mold, the honeycomb grid and the small-diameter through hole 702 of the male mold, and finally exits the mold through the end face hollow hole 705, forming an upward airflow thrust on the honeycomb hole wall. The gas flow rate is set so that the upward thrust of the heated and melted phenolic resin on the honeycomb cell wall before solidification is equivalent to the gravity of the resin flowing downward. The phenolic resin remains solidified in place to avoid flowing to the bottom of the honeycomb to block the cells, and the density uniformity in the thickness direction of the honeycomb is ensured. After the honeycomb high temperature curing process is completed, it is cooled to room temperature, the female mold 6 of the honeycomb shaping mold is removed, the stretching cloth ring 501 is removed from the hooks 606 of all the female molds 6 of the honeycomb shaping mold, and the honeycomb core is taken out; Step 5: local density improvement of the honeycomb core 3: The honeycomb core 3 is moved to the spraying tool, and the honeycomb low-density area 302 is shielded and protected with a film, and the spraying tool is moved to the robot spraying position for positioning; The spraying program is called, and the robot's mechanical arm drives the spray head to spray the phenolic resin glue along the inner surface of the honeycomb core to increase the glue content in the high-density area 301 of the honeycomb core; The phenolic resin glue is diluted with industrial alcohol to a set density; the glue content of the honeycomb high-density area 301 is evenly increased to the design weight requirement by repeatedly spraying glue, drying, and weighing; After drying, the protective film is removed, the honeycomb core 3 is moved back to the honeycomb shaping mold, the stretching cloth rings 501 are all re-hung on the hooks 606 of the female mold 6 of the honeycomb shaping mold, the mold is locked, and the mold is sent into the oven; According to step 4, the honeycomb core 3 is cured at high temperature for the second time, and after being cooled to room temperature, the male mold 7 of the honeycomb shaping mold is removed, and the honeycomb core 3 is taken out; Step 6: Edge processing of the honeycomb core 3: The honeycomb core 3 is placed in the female mold of the fairing shell, and the designed edge of the fairing honeycomb core is marked, and the net size of the honeycomb core 3 is cut according to the marked line. The honeycomb chamfer area 303 is processed on the edges of the honeycomb core 3, and the honeycomb cells of the honeycomb chamfer area 303 are filled with solid foam glue to complete the preparation of the conformal aramid honeycomb core 3.

[0036] A method for forming an aramid honeycomb sandwich structure rocket fairing shell, the method comprising the following steps: Step 1: Preparation of the outer panel 201 of the housing: The carbon fiber prepreg is laid on the female mold surface of the fairing shell 1. After the designed number of layers are laid, a vacuum bag system is laid and the product is sent to an autoclave for high-temperature pressurization and curing; After laying three layers, vacuum bag press is used to perform vacuum pre-compaction to remove the air trapped between layers and improve the quality of the laying.

[0037] After the solidified outer shell panel 201 cools, it is demoulded, the excess is cut off according to the edge line, the inner surface is fully polished to the set roughness, dust is sucked off, and it is wiped clean with a detergent; Put the outer panel 201 of the shell back into the female mold, use high-temperature tape to position it, evenly apply a layer of primer on the inner surface, then lay a layer of high-temperature adhesive film 203, and apply another layer of primer on the adhesive film 203; Step 2: Gluing the conformable aramid honeycomb core 3: The preformed conformable aramid honeycomb core 3 is conformably placed in the outer panel 201 of the shell, with the outer surface in contact with the high-temperature adhesive film 203, a layer of primer is evenly applied on the inner surface of the honeycomb core 3, and then a layer of high-temperature adhesive film 203 is laid, and another layer of primer is applied on the adhesive film; Step 3: Laying of the inner panel 202 of the shell: A carbon fiber prepreg layer is laid on the high temperature adhesive film 203 on the inner surface of the honeycomb core 3, and the prepreg around the edge area of ​​the shell inner panel 202 is directly in contact with the shell outer panel 201. After laying the designed number of layers, the prepreg of the shell inner panel 202 completely wraps the honeycomb core 3; After laying every three layers, use a vacuum bag press to perform vacuum pre-compaction to remove the air trapped between layers and improve the quality of the laying.

[0038] Step 4: Co-curing of the fairing shell 1: A high-temperature vacuum bag system is laid on the inner panel 202 of the shell, and the system is sent into an autoclave for high-temperature pressurized co-curing and molding. After the curing is completed, the system is cooled to room temperature, and the product is taken out to complete the molding of the aramid honeycomb sandwich structure rocket fairing shell 1.

[0039] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An aramid honeycomb sandwich structure rocket fairing shell, comprising a fairing shell (1), characterized in that: The front end of the fairing shell (1) is a conical section (101), the middle and rear ends are cylindrical sections (102), and the fairing shell (1) is composed of a shell outer panel (201), a shell inner panel (202), and a honeycomb core (3) located therebetween to form a co-cured integrally formed structure.

2. The aramid honeycomb sandwich structure rocket fairing shell according to claim 1, characterized in that: The honeycomb core (3) comprises, from the front end to the rear end, a honeycomb high-density area (301), a honeycomb low-density area (302) and a honeycomb chamfer area (303).

3. The aramid honeycomb sandwich structure rocket fairing shell according to claim 2, characterized in that: The honeycomb core (3) is formed by stretching and curing a white honeycomb (4), wherein stretch cloth strips (5) are glued to the upper and lower surfaces of the laminated straight strips of the white honeycomb (4), and uniformly distributed stretch cloth rings (501) are provided on the stretch cloth strips.

4. A honeycomb core forming mold according to claim 3, characterized in that: The honeycomb shaping mold comprises a female mold (6), a male mold (7) and a guide locking structure. The female mold (6) and the male mold (7) are molded and fixed by the guide locking structure.

5. A honeycomb core forming mold according to claim 4, characterized in that: The honeycomb shaping mold female mold (6) is provided with a concave female mold forming mold surface (601), and the female mold forming mold surface (601) is evenly distributed with female mold small-diameter through holes (602). The honeycomb shaping mold female mold (6) is a hollow structure, and a quick-connect air nozzle (605) is installed on the side wall of the honeycomb shaping mold female mold (6), and a hook (606) is provided at the edge of the notch of the honeycomb shaping mold female mold (6).

6. A honeycomb core forming mold according to claim 5, characterized in that: The male mold (7) of the honeycomb shaping mold is provided with a raised male mold shaping mold surface (701) that cooperates with the female mold shaping mold surface (601), and male mold small-diameter through holes (702) are evenly distributed on the male mold shaping mold surface (701). The male mold (7) of the honeycomb shaping mold is a hollow structure, and its end surface is provided with a plurality of end surface hollow holes (705), and hook avoidance grooves (706) are symmetrically provided on both sides of the female mold shaping mold surface (601).

7. A honeycomb core forming mold according to claim 6, characterized in that: The guide locking structure comprises a guide column (603) and a locking screw hole (604) arranged on a female mold (6) of a honeycomb shaping mold, and a guide sleeve (703) and a bolt through hole (704) arranged on a male mold (7) of a honeycomb shaping mold. The guide column (603) and the guide sleeve (703) cooperate with each other, a locking bolt (8) is inserted into the bolt through hole (704), and the locking bolt (8) is threadedly connected to the locking screw hole (604).

8. A method for processing a honeycomb core using a honeycomb core forming mold according to claim 7, characterized in that: The method comprises the following steps: Step 1: Preparation of high-thickness laminated straight strips: The length of the glue-coated aramid paper and the number of staggered stacking layers are set according to the L- and W-direction dimensions of the honeycomb core (3), and edge processing allowance is reserved. After the stacking is solidified, the width of the stacking strips is set according to the thickness of the honeycomb core (3) and cut, and the stretching cloth strips (5) are glued to the upper and lower surfaces of the stacking strips, and the stretching cloth strips are provided with evenly distributed stretching cloth rings (501); Step 2: First stretching and dipping of white honeycomb (4): Stretching the laminated straight strips into a white honeycomb (4) whose cells are not fully expanded, the length of the white honeycomb (4) being suitable for the stretching cloth ring (501) to be fixed on the hook (606) of the dipping tool, and the white honeycomb (4) and the dipping tool are immersed in a phenolic glue pool for dipping; The phenolic resin glue is diluted to a set density using industrial alcohol; the aramid paper is impregnated with the glue by repeatedly dipping, airing, turning, drying, and weighing, so that the glue content of the white honeycomb (4) reaches the weight requirement of the honeycomb low-density area (302) of the honeycomb core (3), and the glue content of the aramid paper is uniform; Step 3: Second stretching of white honeycomb (4): The white honeycomb (4) is moved to the honeycomb shaping mold for a second stretching, and bidirectional radial stretching is performed along the male mold forming mold surface (701) of the honeycomb shaping mold male mold (7). When the mold is in place, the cells of the white honeycomb (4) are stretched into a regular hexagon. The mold locking bolt (8) is screwed and locked with the mold locking screw hole (604) through the bolt through hole (704); Step 4: The honeycomb core (3) is cured and shaped for the first time: After the honeycomb shaping mold is closed, it is moved into an oven, and the quick-connect air nozzle (605) of the female mold (6) of the honeycomb shaping mold is connected to a high-pressure air source, and the air flows through the small-diameter through holes (602) of the female mold, the honeycomb cells and the small-diameter through holes (702) of the male mold, and finally exits the mold through the end face hollow holes (705), forming an upward airflow thrust on the honeycomb cell wall; The gas flow rate is set so that the upward thrust of the heated and melted phenolic resin on the honeycomb cell wall before solidification is equivalent to the gravity of the resin flowing downward. The phenolic resin remains solidified in place to avoid flowing to the bottom of the honeycomb to block the cells, and the density uniformity in the thickness direction of the honeycomb is ensured. After the honeycomb high temperature curing process is completed, the honeycomb is cooled to room temperature, the female mold (6) of the honeycomb shaping mold is removed, the stretching cloth ring (501) is removed from the hooks (606) of all the female molds (6) of the honeycomb shaping mold, and the honeycomb core is taken out; Step 5: local density improvement of the honeycomb core (3): The honeycomb core (3) is moved onto a spraying tool, a film is used to cover and protect the low-density area (302) of the honeycomb, and the spraying tool is moved to a position where the robot sprays and positioned; The spraying program is called, and the robot arm drives the spray head to spray the phenolic resin glue along the inner surface of the honeycomb core, thereby increasing the glue content in the high-density area (301) of the honeycomb core; The phenolic resin glue is diluted with industrial alcohol to a set density; the glue content of the honeycomb high-density area (301) is evenly increased to the design weight requirement by repeatedly spraying glue, drying and weighing; After drying, the protective film is removed, the honeycomb core (3) is moved back onto the honeycomb shaping mold, all the stretched cloth rings (501) are re-hung on the hooks (606) of the female mold (6) of the honeycomb shaping mold, the mold is locked, and the mold is placed into an oven; According to step 4, the honeycomb core (3) is subjected to a second high-temperature curing, and after completion, is cooled to room temperature, the male mold (7) of the honeycomb shaping mold is removed, and the honeycomb core (3) is taken out; Step 6: Edge processing of the honeycomb core (3): The honeycomb core (3) is placed in a fairing shell forming female mold, and a line is drawn according to the designed edge of the fairing honeycomb core, and the net size of the honeycomb core (3) is cut according to the line. A honeycomb chamfered area (303) is processed on the edges of the honeycomb core (3), and the honeycomb cells of the honeycomb chamfered area (303) are filled with solid foam glue to complete the preparation of the conformable aramid honeycomb core (3).

9. The method for forming an aramid honeycomb sandwich structure rocket fairing shell according to claim 3, characterized in that: The molding method comprises the following steps: Step 1: Preparation of the outer panel (201) of the housing: Laying carbon fiber prepreg on the female mold surface of the fairing shell (1), laying a designed number of layers, laying a vacuum bag system, and sending it into an autoclave for high-temperature pressure curing; After the solidified outer shell panel (201) is cooled, it is demoulded, the excess is cut off according to the edge line, the inner surface is fully polished to a set roughness, dust is sucked off, and it is wiped clean with a detergent; The outer panel (201) of the shell is placed back into the female mold, positioned using a high-temperature adhesive tape, a layer of primer is evenly applied on the inner surface, a layer of high-temperature adhesive film (203) is then applied, and another layer of primer is applied on the adhesive film (203); Step 2: Gluing the conformable aramid honeycomb core (3): The preformed conformable aramid honeycomb core (3) is conformably placed in the outer panel (201) of the shell so that the outer surface is in contact with the high-temperature adhesive film (203), a layer of primer is evenly applied on the inner surface of the honeycomb core (3), a layer of high-temperature adhesive film (203) is then applied, and another layer of primer is applied on the adhesive film; Step 3: Laying of the shell inner panel (202): A carbon fiber prepreg layer is laid on the high-temperature adhesive film (203) on the inner surface of the honeycomb core (3), and the prepreg in the peripheral edge area of ​​the shell inner panel (202) is directly in contact with the shell outer panel (201). After laying the designed number of layers, the prepreg of the shell inner panel (202) completely wraps the honeycomb core (3); Step 4: Co-curing of the fairing shell (1): A high-temperature vacuum bag system is laid on the inner panel (202) of the shell, and the shell is sent into an autoclave for high-temperature pressurization and co-curing. After curing, the shell is cooled to room temperature and the product is taken out, thereby completing the molding of the aramid honeycomb sandwich structure rocket fairing shell (1).

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