Preparation method of light-weight high-performance composite material flange

Abstract

The application discloses a preparation method of a light high-performance composite material flange and belongs to the technical field of composite materials. The flange is prepared by the following steps: carbon fiber prepreg is directionally laid in a compression molding mold, high-temperature and high-pressure molding is performed, the molded part is subjected to X-ray nondestructive testing after demolding, screw hole positions are mechanically processed, and finally, the flange is bonded and solidified with titanium alloy screws. The carbon fiber directionally laid molded composite flange obtained by the method can replace a metal material flange obtained by machining a titanium alloy material, the product quality is reduced by more than 30%, the charge amount of the shell is simultaneously increased, and the engine power is improved. The composite flange prepared by the method is suitable for a solid rocket engine shell part, and can bear pressure of 13-20 MPa in cooperation with a shell cylinder segment.

Description

Technical Field

[0001] This invention belongs to the field of composite material processing, and specifically relates to a method for preparing a lightweight, high-performance composite material flange. Background Technology

[0002] Fiber-reinforced resin matrix composites possess unique advantages such as high specific strength and specific stiffness, strong designability, good fatigue fracture resistance, corrosion resistance, good structural dimensional stability, and ease of large-area integral molding. They also exhibit special electromagnetic properties and wave-absorbing stealth effects, fully embodying the distinctive characteristics of integrating structural load-bearing and functional properties. Since their introduction in the mid-1960s, they have been widely used in various weapon systems, playing a crucial role in promoting the lightweighting, miniaturization, and high performance of weaponry. Their application in aerospace and aviation equipment structures can result in corresponding weight reductions, an effect unattainable by other advanced technologies. Furthermore, through comprehensive research across disciplines such as composite structure, materials, and processes, as well as interdisciplinary studies in design, electronics, and aerodynamics, the design potential of composite structure and function can be deeply explored. Therefore, the application of advanced resin matrix composites in the aerospace field is becoming increasingly widespread.

[0003] The application of high-performance fibers can improve the overall performance of composite materials, thereby reducing their weight by 15-30%. Reducing the inertial mass of the product not only reduces launch weight but also saves launch costs, allows for carrying heavier damage, or increases effective range and impact accuracy. Calculations show that for every 1kg reduction in the structural mass of the engine, the range increases by approximately 0.6, 3.0, and 16km respectively. Therefore, structural weight reduction, especially of the final stage engine casing, is a constant goal pursued by strategic missile designers, and one of the most important technical approaches to achieving this goal is the use of advanced materials. Carbon fiber composites, using carbon fiber as reinforcement, possess excellent specific stiffness and specific strength, resulting in superior overall performance. They are currently the most widely used advanced composite material and are extensively used in the manufacture of solid rocket engines. Directional layup molding is one of the important methods for molding composite materials. It has good processability and low manufacturing cost. Molded products have good mechanical strength, light weight, good electrical insulation, flame retardancy, corrosion resistance, radiation resistance, ablation resistance, and good resistance to instantaneous high temperature. Many parts of military and civilian products use carbon fiber layup molded composite materials.

[0004] With the increasing demands for flight power and payload performance of various aircraft models, higher requirements are being placed on engine performance. Lightweight and high-load capacity are new requirements for engine research and innovation. All-composite engine combustor casings have emerged to meet these needs. While existing high-performance engine combustor casings are primarily made of composite materials, critical components such as the front and rear flanges are still manufactured using titanium or aluminum alloys, making it difficult to overcome the need for lightweight casings. Summary of the Invention

[0005] The purpose of this invention is to address the bottleneck of existing critical housing components, such as the front and rear flanges, still being made of titanium or aluminum alloys, making it difficult to achieve lightweight housing requirements. This invention provides a lightweight, high-performance composite material flange that can be efficiently mass-produced. The composite flange, manufactured using directional layup of carbon fiber prepreg followed by molding, is characterized by: using high-performance composite materials to manufacture critical housing components like the front and rear flanges, replacing titanium or aluminum alloy parts, thus achieving the goal of lightweight engine manufacturing. The composite material flange weighs only 65% ​​of the metal flange, reducing the weight of housing flange components by more than 30%. Its manufacturing process is advanced, simple, and has high material utilization, not only reducing production costs but also shortening the production cycle. This method belongs to the field of carbon fiber composite material processing technology and has excellent application prospects in the manufacture of aerospace power housings.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] A method for preparing a lightweight, high-performance composite flange, characterized by comprising:

[0008] S1: Prepare raw materials, including carbon fiber prepreg and carbon cloth prepreg;

[0009] S2: Using an automatic cutting system, carbon fiber prepreg and carbon cloth prepreg for directional layup are cut into pieces and labeled;

[0010] S3: Directional layup: Clean the mold cavity for layup until clean, and manually lay up the cut carbon fiber prepreg and carbon cloth prepreg according to the layup plan designed in the process design. After the layup is completed, close the mold.

[0011] S4: Preheating: After the directional layup is completed, the mold with the mold closed is placed in an electric heating drying oven for preheating. After preheating, the mold is taken out of the oven as a whole.

[0012] S5: Pre-pressing: After preheating, the mold is placed into the hydraulic press or vulcanizing machine workbench for pre-pressing. The pre-pressing method is a step-by-step pressurization method.

[0013] S6: Trimming overflow: After pre-pressing, open the mold to trim the overflow of the pre-pressed product, and close the mold after trimming.

[0014] S7: Compression Curing: After the mold is closed, a vacuum bag is attached to the mold, the vacuum pump is turned on to evacuate the mold throughout the process, the upper and lower heating plates of the mold are connected to the power supply for heating, the temperature is automatically controlled according to the temperature control degree set program of the process design, the pressure is increased and the exhaust is carried out according to the temperature system, and then the mold is cured by heat preservation and pressure.

[0015] S8: Cooling: After heat preservation, pressure preservation and curing, disconnect the power supply to the heating plate and allow it to cool and depressurize naturally, but the mold is still vacuumed;

[0016] S9: Demolding: Demold the molded part after the mold has cooled down;

[0017] S10: Internal quality inspection is performed on the molded parts after demolding;

[0018] S11: Machining screw hole positions and metal screws;

[0019] S12: The molded part is bonded and cured with metal screws to obtain the lightweight high-performance composite material flange.

[0020] Preferably, the resin content of the carbon fiber prepreg in step S1 is 30-33%, and the resin content of the carbon cloth prepreg is 38-40%.

[0021] Preferably, the carbon fiber prepreg and carbon cloth prepreg in step S2 need to be thawed before cutting.

[0022] Preferably, before the directional layup in step S3, the mold of the layup part is preheated. After the mold is vacuum-sealed with a release film, breathable felt, vacuum bag and sealing strip, it is placed in an electric heating drying oven at 50-55°C for 1-1.5 hours before being taken out of the oven for layup.

[0023] Preferably, the pre-pressing process in step S5 is performed after the mold is preheated and removed from the furnace. After the mold temperature drops to 30±5℃, it is transferred to the vulcanizing machine for pre-pressing by stepwise pressure.

[0024] Preferably, in step S6, the overflow is trimmed: after pre-pressing is completed, the mold is opened to trim the overflow of the pre-pressed product. After trimming, the outer edge of the prepreg is 0-2mm away from the outer edge of the mold cavity. After trimming, the mold is closed.

[0025] Preferably, the molding curing temperature requirements in step S7 are as follows: the entire molding process is under vacuum, the temperature is manually monitored by instruments during the molding process, and the temperature difference between the upper and lower molds is ≤15℃; otherwise, measures are taken to control it.

[0026] Preferably, in step S8, the cooling process is as follows: after the heat preservation and pressure holding are completed, the power is turned off and the temperature is naturally reduced, the hydraulic press or the pressure replenishing pump of the vulcanizing machine is turned off, and the temperature and pressure are naturally reduced.

[0027] Preferably, demolding is performed when the mold temperature is ≤50℃ in step S9.

[0028] Preferably, the product demolding process in step S9 is as follows: First, the upper mold is symmetrically opened by using a hydraulic jack; then, the bottom connecting bolts of the middle mold are unscrewed; the connection between the middle mold and the lower mold is loosened; 3) the middle mold and the lower mold are separated by screws; 4) the product parts are removed to prevent damage from bumps and knocks.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] 1) The purpose of this invention is to solve the bottleneck that existing critical components of the rocket engine shell, such as the front and rear flanges, are still made of titanium or aluminum alloy, making it difficult to meet the demand for lightweight shells. This invention provides a composite flange component manufactured using carbon fiber directional layup molding, which can be efficiently and lightweightly mass-produced. The characteristics of the composite flange manufactured using carbon fiber directional layup molding are: using high-performance composite materials to prepare the front and rear flanges of critical components, replacing titanium or aluminum alloy metal parts, can achieve the goal of lightweight engine manufacturing. The composite flange weighs only 65% ​​of the metal flange, reducing the weight of the shell flange component by more than 30%, while simultaneously increasing the propellant charge in the shell and improving the engine's power output. The composite flange prepared by this method is suitable for solid rocket engine shell components and, working together with the shell section, can withstand pressures of 13–20 MPa.

[0031] 2) A method for preparing lightweight high-performance composite material flanges can efficiently complete the processing and production of large batches of composite material flanges, and each piece has high dimensional accuracy and excellent quality stability and consistency.

[0032] 3) The composite flanges produced by directional layup molding of carbon fiber are manufactured using an advanced process with a simple flow and high material utilization, which not only reduces production costs but also shortens the production cycle. This method belongs to the field of carbon fiber composite material processing technology and has excellent application prospects in the manufacture of aerospace power casings. Attached Figure Description

[0033] Figure 1 This is a schematic cross-sectional view of a composite material flange molding component.

[0034] Figure 2 This is a schematic diagram of the cross-sectional structure of a composite material flange mold;

[0035] Figure 3 This is a partial cross-sectional structural diagram of a composite material flange.

[0036] In the diagram: 1-Upper mold; 2-Molded part; 3-Middle mold; 4-Lower mold; 5-Titanium alloy screw; D-Outer diameter of molded part; H-Thickness of molded part. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The following is in conjunction with the appendix Figure 1-3 The embodiments of the present invention will be described in further detail below.

[0039] Example 1

[0040] Carbon fiber composite flanges with dimensions of 38mm (thickness) × φ360mm (outer diameter) are produced by layup molding.

[0041] A method for manufacturing a lightweight, high-performance composite material flange, used in the production of front and rear flanges for important shell components, includes the following steps:

[0042] S1: Prepare raw materials, including carbon fiber prepreg and carbon cloth prepreg; wherein the resin content of carbon fiber prepreg is 30% to 33%, the resin content of carbon cloth prepreg is 38% to 40%, and the amount of carbon fiber prepreg is 2 kg and the amount of carbon cloth prepreg is 1.5 kg.

[0043] S2: Using an automatic cutting system, carbon fiber prepreg and carbon cloth prepreg for directional layup are cut into pieces and labeled; the carbon fiber prepreg and carbon cloth prepreg need to be thawed before cutting.

[0044] S3: Directional Layup: Clean the mold cavity for layup to a clean state. According to the layup plan designed in the process design, manually lay up the cut carbon fiber prepreg and carbon cloth prepreg in a directional manner. After layup is completed, close the mold. Before directional layup, preheat the mold of the layup parts. After vacuuming the mold with a release film, breathable felt, vacuum bag, and sealing strip, place the mold in an electric heating drying oven at 50℃~55℃ for 1h~1.5h before laying up.

[0045] S4: Preheating: After the directional layup is completed, the mold with the mold closed is placed in an electric heating drying oven for preheating. After preheating, the mold is taken out of the oven as a whole.

[0046] S5: Pre-pressing: After the mold has been preheated and removed from the furnace, it is placed into the hydraulic press or vulcanizing machine workbench for pre-pressing. The pre-pressing process is to remove the mold from the furnace after preheating, and after the mold temperature drops to 35±5℃, it is moved to the vulcanizing machine for pre-pressing by step-by-step pressure.

[0047] S6: Trim overflow: After pre-pressing, open the mold to trim the overflow of the pre-pressed product; after trimming, the outer edge of the prepreg is 0-2mm away from the outer edge of the mold. After trimming, close the mold.

[0048] S7: Molding and Curing: After mold closing, a vacuum bag is attached to the mold. The vacuum pump is turned on to evacuate the mold throughout the process. The upper and lower heating plates of the mold are powered on and heated. The temperature is automatically controlled according to the temperature control program set in the process design. Pressure is applied and vented according to the temperature regime, and then the mold is cured by heat preservation and pressure holding. The entire molding process is carried out under vacuum. The temperature is manually monitored during the molding process to ensure that the temperature difference between the upper and lower molds is ≤15℃. Otherwise, control measures are taken.

[0049] S8: Cooling: After heat preservation, pressure preservation and curing, disconnect the power supply to the heating plate, turn off the hydraulic press or vulcanizing machine pressure pump, and allow it to cool down and depressurize naturally, but the mold is still vacuumed.

[0050] S9: Demolding: Demolding when the mold temperature is ≤50℃; 1) First, use a hydraulic jack to symmetrically open the upper mold 1; 2) Unscrew the bottom connecting bolts of the middle mold 3; loosen the connection between the middle mold 3 and the lower mold 4. 3) Separate the middle mold 3 and the lower mold 4 with screws. 4) Take out the molded part 2, allowing for molded fiber flash.

[0051] S10: The interior of molded part 2 undergoes non-destructive X-ray quality inspection;

[0052] S11: Machining screw holes and titanium alloy screws 5;

[0053] S12: The molded part 5 is bonded and cured with the titanium alloy screw 5 to obtain a composite material flange after curing.

[0054] Example 2

[0055] Carbon fiber composite flanges with a thickness of 50mm × φ660mm (outer diameter) are produced by layup molding.

[0056] A method for manufacturing a composite flange made of carbon fiber directional layup molding, used for the production of front and rear flanges of important shell components, includes the following steps:

[0057] S1: Prepare raw materials, including carbon fiber prepreg and carbon cloth prepreg; wherein the resin content of carbon fiber prepreg is 30% to 33%, the resin content of carbon cloth prepreg is 38% to 40%, and the amount of carbon fiber prepreg is 12 kg and the amount of carbon cloth prepreg is 6 kg.

[0058] S2: Using an automatic cutting system, carbon fiber prepreg and carbon cloth prepreg for directional layup are cut into pieces and labeled; the carbon fiber prepreg and carbon cloth prepreg need to be thawed before cutting.

[0059] S3: Directional Layup: Clean the mold cavity for layup to a clean state. According to the layup plan designed in the process design, manually lay up the cut carbon fiber prepreg and carbon cloth prepreg in a directional manner. After layup is completed, close the mold. Before directional layup, preheat the mold of the layup parts. After vacuuming the mold with a release film, breathable felt, vacuum bag, and sealing strip, place the mold in an electric heating drying oven at 50℃~55℃ for 1h~1.5h before laying up.

[0060] S4: Preheating: After the directional layup is completed, the mold with the mold closed is placed in an electric heating drying oven for preheating. After preheating, the mold is taken out of the oven as a whole.

[0061] S5: Pre-pressing: After the mold has been preheated and removed from the furnace, it is placed into the hydraulic press or vulcanizing machine workbench for pre-pressing. The pre-pressing process is to remove the mold from the furnace after preheating, and after the mold temperature drops to 35±5℃, it is moved to the vulcanizing machine for pre-pressing by step-by-step pressure.

[0062] S6: Trim overflow: After pre-pressing, open the mold to trim the overflow of the pre-pressed product; after trimming, the outer edge of the prepreg is 0-2mm away from the outer edge of the mold. After trimming, close the mold.

[0063] S7: Molding and Curing: After mold closing, a vacuum bag is attached to the mold, the vacuum pump is turned on to evacuate the mold throughout the process, the upper and lower heating plates of the mold are connected to the power supply for heating, the temperature is automatically controlled according to the temperature control program set in the process design, the pressure is increased and the air is vented according to the temperature regime, and then the mold is cured by heat preservation and pressure. The entire molding process is carried out under vacuum. During the molding process, the instrument temperature is manually monitored to ensure that the temperature difference between the upper and lower molds is ≤15℃, otherwise measures are taken to control it.

[0064] S8: Cooling: After heat preservation, pressure preservation and curing, disconnect the power supply to the heating plate, turn off the hydraulic press or vulcanizing machine pressure pump, and allow it to cool down and depressurize naturally, but the mold is still vacuumed.

[0065] S9: Demolding: Demolding when the mold temperature is ≤50℃; 1) First, use a hydraulic jack to symmetrically open the upper mold 1; 2) Unscrew the bottom connecting bolts of the middle mold 3; loosen the connection between the middle mold 3 and the lower mold 4; 3) Separate the middle mold 3 and the lower mold 4 with screws; 4) Take out the molded part 2, allowing for molded fiber flash.

[0066] S10: The interior of molded part 2 undergoes non-destructive X-ray quality inspection;

[0067] S11: Machining screw holes and titanium alloy screws 5;

[0068] S12: The molded part 2 is bonded and cured with the titanium alloy screw 5, and a composite material flange is obtained after curing.

[0069] Based on the description and accompanying drawings of this invention, those skilled in the art can easily manufacture or use the lightweight high-performance composite flange and its preparation method as described in this invention, and can achieve the positive effects described in this invention.

[0070] Unless otherwise specified, in this invention, terms such as "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe orientation or positional relationships in this invention are for illustrative purposes only and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood in conjunction with the accompanying drawings and according to the specific circumstances.

[0071] Unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a lightweight, high-performance composite material flange, characterized in that, include: S1: Prepare raw materials, including carbon fiber prepreg and carbon cloth prepreg; S2: Using an automatic cutting system, carbon fiber prepreg and carbon cloth prepreg for directional layup are cut into pieces and labeled; S3: Directional layup: Clean the mold cavity for layup until clean, and manually lay up the cut carbon fiber prepreg and carbon cloth prepreg according to the layup plan of the process design. After layup is completed, close the mold. Before directional layup, preheat the mold of the layup part. After vacuuming the mold with a release film, breathable felt, vacuum bag and sealing strip, put the mold into an electric heating drying oven at 50-55℃ for 1-1.5h before laying up. S4: Preheating: After the directional layup is completed, the mold with the mold closed is placed in an electric heating drying oven for preheating. After preheating, the mold is taken out of the oven as a whole. S5: Pre-pressing: After the preheating is completed, the mold is placed into the hydraulic press or vulcanizing machine workbench for pre-pressing. The pre-pressing method is a step-by-step press. The pre-pressing process is that after the mold is preheated, it is taken out of the furnace and after the mold temperature drops to 30±5℃, it is moved to the vulcanizing machine for pre-pressing by step-by-step press. S6: Trimming overflow: After pre-pressing, open the mold to trim the overflow of the pre-pressed product, and close the mold after trimming. S7: Compression Curing: After the mold is closed, a vacuum bag is attached to the mold, the vacuum pump is turned on to evacuate the mold throughout the process, the upper and lower heating plates of the mold are connected to the power supply for heating, the temperature is automatically controlled according to the temperature control degree set program of the process design, the pressure is increased and the exhaust is carried out according to the temperature system, and then the mold is cured by heat preservation and pressure. S8: Cooling: After heat preservation, pressure preservation and curing, disconnect the power supply to the heating plate and allow it to cool and depressurize naturally, but the mold is still vacuumed; S9: Demolding: Demold the molded part after the mold has cooled down; S10: Internal quality inspection is performed on the molded parts after demolding; S11: Machining screw holes and metal screws; S12: The molded part is bonded and cured with metal screws to obtain the lightweight high-performance composite material flange.

2. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: In step S1, the resin content of the carbon fiber prepreg is 30-33%, and the resin content of the carbon cloth prepreg is 38-40%.

3. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: In step S2, the carbon fiber prepreg and carbon cloth prepreg need to be thawed before cutting.

4. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: In step S6, the overflow is trimmed: After pre-pressing is completed, the mold is opened to trim the overflow of the pre-pressed product. After trimming, the outer edge of the prepreg is 0-2mm away from the outer edge of the mold cavity. After trimming, the mold is closed.

5. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: The molding and curing temperature requirements in step S7 are as follows: the entire molding process is under vacuum, and the temperature is monitored manually to ensure that the temperature difference between the upper and lower molds is ≤15℃; otherwise, control measures are taken.

6. The method for preparing a lightweight high-performance composite flange according to claim 1, characterized in that: In step S8, the cooling process is as follows: After the heat preservation and pressure holding are completed, the power is turned off and the temperature is allowed to drop naturally. The hydraulic press or the pressure boosting pump of the vulcanizing machine is turned off and the temperature and pressure are allowed to drop naturally.

7. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: Demolding is performed when the mold temperature is ≤50℃ in step S9.

8. The method for preparing the lightweight high-performance composite flange according to claim 1, characterized in that: The demolding process in step S9 is as follows: First, use a hydraulic jack to symmetrically open the upper mold; unscrew the connecting bolts at the bottom of the middle mold; loosen the connection between the middle mold and the lower mold; 3) separate the middle mold and the lower mold with screws; 4) remove the product parts to prevent them from being bumped or damaged.

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