Method for improving yield of composite material formed by resin transfer molding process

Abstract

The invention relates to a method for improving the yield of a composite material formed by a resin transfer molding process, the method is applied to a composite material formed by the resin transfer molding process, and the composite material formed by the resin transfer molding process comprises a forming mold and a woven composite material fan blade; the fan blade made of the woven composite material comprises a tenon, a transition area, a blade front edge and a blade body, the forming die is provided with a glue inlet at the tenon, a first resin channel at the transition area, a second resin channel and a third resin channel at the blade front edge, a fourth resin channel and a fifth resin channel at the blade body, and a glue outlet at the tail end. According to the method for improving the yield of the composite material formed by the resin transfer molding process, a plurality of glue inlets / outlets are adopted, and a controllable glue inlet / outlet form is adopted, so that the forming quality of the woven composite material fan blade is remarkably improved.

Description

Technical Field

[0001] This application relates to the technical field of liquid molding of resin matrix composites, and particularly to a method for improving the finished product rate of composites formed by resin transfer molding process. Background Art

[0002] Carbon fiber reinforced resin matrix composites have unique advantages such as light weight, high specific strength, high specific modulus, good anti-fatigue fracture performance, corrosion resistance, and being convenient for large-area integral forming. They have been widely used in the structures of aircraft and engines, and have become key materials for aviation equipment. Their usage has also become one of the symbols of the advancement of aviation equipment.

[0003] Woven composites are composites formed by interweaving two or more reinforcing fibers to form an integral structure. Compared with two-dimensional laminated structure composites, woven composites have a completely integral and non-laminated structure, overcoming the disadvantage that traditional laminated composites are prone to delamination when stressed. They can be used to manufacture integral structure parts and functional parts. Therefore, the composite fan blades formed by the woven / resin transfer molding (RTM) process not only have better impact resistance, but also the RTM process can better ensure the shape accuracy and high consistency of the product. Currently, it has become one of the development and application directions of composite fan blades for large bypass ratio engines.

[0004] However, the woven composite fan blade is a large torsion variable cross-section complex curved surface structure, which has extremely high requirements for forming quality and forming accuracy. Since the woven composite fan blade is a non-homogeneous structure, especially affected by the anti-bird strike impact performance, there are different designs and higher quality requirements for the blade leading edge and the area of the blade leading edge root. The most significant feature is the use of a higher fiber volume fraction (≥60%) and a more complex structure design, and there are also higher requirements for the internal quality. Usually, the maximum diameter of a single internal pore is <1 - 3 mm, and the porosity is <0.5%. At the same time, in order to ensure that the blade has excellent anti-foreign object impact ability, resins with high toughness and short aging characteristics are used during RTM molding, such as RTM230ST of Hexcel Corporation, PR520 of Cytec Corporation, and ACTECH 1304 resin of AVIC Composite Materials. Since the injection temperature of this type of resin is relatively high (>160°C), while the curing temperature is only 180°C, the reaction activity of the resin at the injection temperature is very high, and the risk of explosive polymerization is higher than that of conventional resins. At the same time, the effective injection period of this type of resin is extremely short (<35 min), and it is very difficult to form normally using the conventional RTM molding process. Therefore, it greatly increases the difficulty of forming the blade. Summary of the Invention

[0005] The technical problem to be solved by this application is:

[0006] When forming a composite fan blade by RTM, it is very easy to have defects such as pores due to the resin injection speed being too fast, which causes the resin not to be fully infiltrated inside the product, and is not conducive to the high-quality control of the product.

[0007] To solve the above problems, the present application provides a method for improving the yield of composite materials formed by the resin transfer molding process, which is applied to the composite material system formed by the resin transfer molding process. The composite material system formed by the resin transfer molding process includes a molding die and a woven composite fan blade;

[0008] The woven composite fan blade includes a tenon, a transition zone, a leading edge and a blade body; the molding die is provided with a resin inlet at the tenon, a first resin channel at the transition zone, a second resin channel and a third resin channel at the leading edge, a fourth resin channel and a fifth resin channel at the blade body, and a resin outlet at the end;

[0009] The method for improving the yield of composite materials formed by the resin transfer molding process includes:

[0010] S1. Place the woven composite fan blade into the molding die and close the die, and heat the entire composite material system formed by the resin transfer molding process to the injection temperature;

[0011] S2. Inject the resin into the woven composite fan blade through the resin inlet on the molding die. The initial injection pressure value is P0. After maintaining for 1 - 5 minutes, gradually increase the injection pressure value to P1 until the resin flows out from the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, the fifth resin channel and the resin outlet in sequence;

[0012] S3. Close the first resin channel, the second resin channel, the third resin channel, the fourth resin channel and the fifth resin channel in sequence, connect a resin source to each resin channel, and apply pressure respectively. The injection pressure value is P2;

[0013] S4. Open the first resin channel, the second resin channel, the third resin channel, the fourth resin channel and the fifth resin channel in sequence, and make the resin enter the molding die from each resin channel to inject the woven composite fan blade again for 10 - 15 minutes;

[0014] S5. Gradually increase the injection pressure at the resin inlet to P2 and close the resin outlet;

[0015] S6. Increase the injection pressure of the first resin channel to P3;

[0016] S7. Heat up the composite material system formed by the entire resin transfer molding process. When the system reaches the resin curing and heat preservation temperature, sequentially close the resin inlet, the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel.

[0017] Further, after step S7, it further includes:

[0018] S8. After the woven composite fan blade is cured, take it out of the molding die.

[0019] Further, the fiber volume fraction of the tenon is 50% - 52%, the fiber volume fraction of the transition zone is 52% - 62%, the fiber volume fraction of the leading edge of the blade is 60% - 62%, and the fiber volume fraction of the blade body is 58% - 60%.

[0020] Further, the injection temperature is 160 - 170 °C.

[0021] Further, step S2 is controlled within 15 minutes.

[0022] Further, the whole process from step S2 to S6 is controlled within 35 minutes.

[0023] Further, the resin curing and heat preservation temperature is 180 °C.

[0024] Further, the injection pressure values satisfy P0 < P1 < P2 < P3.

[0025] Further, P0 is 0 - 0.5 MPa, P1 is 0.6 - 0.8 MPa, P2 is 0.9 - 1.1 MPa, and P3 is 1.2 - 1.5 MPa.

[0026] Further, the fracture energy G of the resin IC ≥1000 J / m 2 .

[0027] The above technical solution of the present application has the following advantages:

[0028] The method for improving the yield of composite materials formed by the resin transfer molding process provided by the present application forms the woven composite fan blade by adopting a multi-point controllable pressure injection method with multiple resin inlets / outlets and an alternating multi-point controllable resin inlet / outlet mode, significantly improving the molding quality of the woven composite fan blade. For different structural regions of the woven composite fan blade, different resin injection forms are adopted. For regions with a low fiber volume fraction, a slow-flow injection form is used; for regions with a medium fiber volume fraction, the injection pressure is further increased; for regions with a high fiber volume fraction, a supersaturated injection method is used, further improving the molding quality of the product. Description of the Drawings

[0029] To more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 Schematic diagram of the woven composite fan blade provided by the present application;

[0031] Figure 2 Combined schematic diagram of the molding die and the woven composite fan blade provided by the present application.

[0032] Reference numerals: 1, tenon; 2, transition zone; 3, leading edge of the blade; 4, blade body; 10, woven composite fan blade; 20, resin inlet; 31, first resin channel; 32, second resin channel; 33, third resin channel; 34, fourth resin channel; 35, fifth resin channel; 40, resin outlet; 50, molding die. Specific embodiments

[0033] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0034] It should be understood that when used in the specification and appended claims of the present application, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0035] In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0036] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but rather mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized. "Plurality" means "two or more".

[0037] In view of the deficiencies of the traditional resin transfer molding composite material technology, this application proposes a method for improving the yield of composite materials formed by the resin transfer molding process.

[0038] The following will further describe in detail the specific implementation manners of this application in conjunction with the drawings and embodiments. The following embodiments are used to illustrate this application, but are not used to limit the scope of this application.

[0039] The method for improving the yield of composite materials formed by the resin transfer molding process provided by the embodiments of this application is applied to a composite material system formed by the resin transfer molding process. The composite material system formed by the resin transfer molding process includes a molding die and a woven composite fan blade; the woven composite fan blade includes a tenon, a transition zone, a leading edge, and a blade body; the molding die is provided with a resin inlet at the tenon, a first resin channel at the transition zone, a second resin channel and a third resin channel at the leading edge, a fourth resin channel and a fifth resin channel at the blade body, and a resin outlet at the end.

[0040] The method for improving the yield of composite materials formed by the resin transfer molding process includes:

[0041] S1. Place the woven composite fan blade into the molding die and close the die, and heat the entire composite material system formed by the resin transfer molding process to the injection temperature.

[0042] S2. Inject the resin into the woven composite fan blade through the resin inlet on the molding die. The initial injection pressure value is P0. After maintaining for 1 - 5 minutes, gradually increase the injection pressure value to P1 until the resin flows out from the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, the fifth resin channel, and the resin outlet in sequence.

[0043] S3. Close the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel in sequence. Connect a resin source to each resin channel and apply pressure respectively, with the injection pressure value being P2;

[0044] S4. Open the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel in sequence, so that the resin enters the molding die from each resin channel and reinjects into the woven composite fan blade for 10 - 15 minutes;

[0045] S5. Gradually increase the injection pressure at the glue inlet to P2 and close the glue outlet;

[0046] S6. Increase the injection pressure of the first resin channel to P3;

[0047] S7. Heat up the entire resin transfer molding process - formed composite material system. When the system reaches the resin curing and heat - preservation temperature, close the glue inlet, the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel in sequence.

[0048] In some embodiments, after step S7, it further includes:

[0049] S8. After the woven composite fan blade is cured, take it out from the molding die.

[0050] In some embodiments, the fiber volume fraction of the tenon is 50% - 52%, the fiber volume fraction of the transition zone is 52% - 62%, the fiber volume fraction of the leading edge of the blade is 60% - 62%, and the fiber volume fraction of the blade body is 58% - 60%.

[0051] In some embodiments, the injection temperature is 160 - 170 °C.

[0052] In some embodiments, step S2 is controlled within 15 minutes.

[0053] In some embodiments, the whole process from step S2 to S6 is controlled within 35 minutes.

[0054] In some embodiments, the resin curing and heat - preservation temperature is 180 °C.

[0055] In some embodiments, the injection pressure values satisfy P0 < P1 < P2 < P3.

[0056] In some embodiments, P0 is 0 - 0.5 MPa, P1 is 0.6 - 0.8 MPa, P2 is 0.9 - 1.1 MPa, and P3 is 1.2 - 1.5 MPa.

[0057] In some embodiments, the fracture energy G of the resinIC ≥1000 J / m 2 。

[0058] As Figure 1 and Figure 2 shown, the resin transfer molding process composite material system includes a molding die 50 and a woven composite fan blade 10. The woven composite fan blade 10 has a variable fiber volume fraction structure and is composed of a tenon 1, a transition zone 2, a leading edge 3 of the blade, and a blade body 4; the fiber volume fraction of the tenon 1 is 50% - 52%, the fiber volume fraction of the transition zone 2 is 52% - 62%, the fiber volume fraction of the leading edge 3 of the blade is 60% - 62%, and the fiber volume fraction of the blade body 4 is 58% - 60%.

[0059] The method for improving the yield of the composite material formed by the resin transfer molding process includes the following steps:

[0060] 1) Place the woven composite fan blade 10 into the molding die 50 and close the die, and heat the entire system to the injection temperature of 160 - 170 °C;

[0061] 2) Inject resin into the woven composite fan blade 10 through the resin inlet 20 on the molding die 50 by pressure. The initial injection pressure value is P0. After maintaining for 1 - 5 min, gradually increase the injection pressure value to P1 until resin flows out from the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, the fifth resin channel 35, and the resin outlet 40 in sequence. This step is controlled within 15 min;

[0062] 3) Close the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35 in sequence. Connect a resin source to the resin channels and apply pressure respectively. The injection pressure value is P2;

[0063] 4) Open the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35 in sequence, so that the resin enters the mold from the above channels and reinjects into the woven composite fan blade 10 for 10 - 15 min;

[0064] 5) Gradually increase the injection pressure of the resin inlet 20 to P2 and close the resin outlet 40;

[0065] 6) Increase the injection pressure of the first resin channel 31 to P3;

[0066] 7) The whole process of steps 2 - 6 needs to be controlled within about 35 min;

[0067] 8) Heat up the entire system. When the system reaches the resin curing and heat preservation temperature (180 °C), sequentially close the glue inlet 20, the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35;

[0068] 9) After the woven composite fan blade 10 is cured, take it out of the molding die 50.

[0069] Among them, the injection pressure values P0 < P1 < P2 < P3; the starting injection pressure value P0 ranges from 0 to 0.5 MPa, the injection pressure value P1 ranges from 0.6 to 0.8 MPa, the injection pressure value P2 ranges from 0.9 to 1.1 MPa, and the injection pressure P3 ranges from 1.2 to 1.5 MPa. The fracture energy G IC ≥1000 J / m 2 is required for molding with a high toughness resin.

[0070] This application adopts a form of multi-point alternating controllable glue inlet and outlet, and forms the woven blade by a form of multi-point controllable pressure injection. For different structural regions of the woven blade, different resin injection forms are adopted. For regions with a low fiber volume fraction, a slow-flow injection form is adopted. For regions with a medium fiber volume fraction, the injection pressure is further increased. For regions with a high fiber volume fraction, a supersaturated injection method is adopted, which further improves the molding quality of the product.

[0071] The woven composite fan blade adopts Z-direction fibers to improve the interlayer performance, so it has better impact resistance, and different woven structures and materials can be used for optimization design, which is more conducive to improving the foreign object impact resistance of the engine, making the engine have better safety. It is an advanced new lightweight composite fan blade and can be widely used in various commercial high-bypass ratio engines, which can generate extremely high economic and social benefits.

[0072] The following is illustrated through specific embodiments.

[0073] Embodiment

[0074] A woven composite fan blade 10 is woven by 2.5D of CCF800G carbon fiber. Among them, the fiber volume fraction in the tenon region is 52%, the fiber volume fraction in the blade body region is 58%, the fiber volume fraction in the leading edge region of the blade is 60%, and the fiber volume fraction at the root of the leading edge of the blade is 62%. The resin used is ACTECH1304 of AVIC Composite Materials Co., Ltd.

[0075] The specific implementation steps are as follows:

[0076] 1) Place the woven composite fan blade 10 into the molding die 50 and close the mold, and heat up the entire system to the injection temperature of 165 °C;

[0077] 2) Inject the resin into the woven composite fan blade 10 through the resin inlet 20 on the molding die 50 under pressure. The initial injection pressure value is 0.3 MPa. After maintaining for 3 min, gradually increase the injection pressure value to 0.7 MPa until the resin flows out from the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, the fifth resin channel 35, and the resin outlet 40 in sequence. This step is controlled within 15 min.

[0078] 3) Close the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35 in sequence. Connect a resin source to the resin channels and apply pressure respectively. The injection pressure value is 1.0 MPa.

[0079] 4) Open the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35 in sequence, and allow the resin to enter the mold from the above channels to reinject the woven composite fan blade 10 for 12 min.

[0080] 5) Gradually increase the injection pressure at the resin inlet 20 to 1.0 MPa and close the resin outlet 40.

[0081] 6) Increase the injection pressure of the first resin channel 31 to 1.2 MPa.

[0082] 7) The whole process of steps 2 - 6 needs to be controlled within about 35 min.

[0083] 8) Heat up the whole system. When the system reaches the resin curing and heat preservation temperature (180 °C), close the resin inlet 20, the first resin channel 31, the second resin channel 32, the third resin channel 33, the fourth resin channel 34, and the fifth resin channel 35 in sequence.

[0084] 9) After the woven composite fan blade 10 is cured, take it out from the molding die 50.

[0085] This application significantly improves the molding quality of the woven composite fan blade, reduces the possibility of internal porosity occurrence, especially in the leading edge and transition zone areas of the blade with a high fiber volume fraction, and can greatly improve the internal quality of the molding. This application is particularly suitable for the rapid RTM molding process or the high-temperature resin short-time RTM process. The resin operation time of the rapid RTM process is extremely short, and a high requirement is imposed on the effective operation period of the resin; while the resin injection temperature of the high-temperature RTM process is relatively high, and the operation period of the resin is also short. This application realizes the manufacturing of the woven composite fan blade, which can balance high efficiency and low cost, and has more cost and manufacturing efficiency advantages than the existing two-dimensional laminated structure composite fan blade.

[0086] In summary, the method for improving the yield of composite material products formed by the resin transfer molding process proposed in this application can significantly improve the yield of RTM-formed woven composite fan blade parts.

[0087] It should be clear that each embodiment in this specification is described in a progressive manner. For the same or similar parts between each embodiment, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments. This application is not limited to the specific structure described above and shown in the figures. And, for the sake of brevity, the detailed description of known method technologies is omitted here.

[0088] The above-described embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of this application, and should all be included within the protection scope of this application.

Claims

1. A method for improving the yield rate of composite materials formed by resin transfer molding process, characterized in that: A composite material system is applied to a resin transfer molding process, wherein the composite material system comprises a molding die and a woven composite material fan blade; The woven composite fan blade comprises a tenon, a transition zone, a blade leading edge and a blade body; the molding die is provided with a glue inlet at the tenon, a first resin channel at the transition zone, a second resin channel and a third resin channel at the blade leading edge, a fourth resin channel and a fifth resin channel at the blade body, and a glue outlet at the end; The method for improving the yield rate of composite materials formed by resin transfer molding process comprises: S1, placing the woven composite fan blade into a molding mold and closing the mold, and heating the entire resin transfer molding process molding composite system to an injection temperature; S2, injecting resin into the woven composite fan blade through the glue inlet on the molding die, with the initial injection pressure value being P0, maintaining for 1 to 5 minutes, and then gradually increasing the injection pressure value to P1 until the resin flows out of the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, the fifth resin channel and the glue outlet in sequence; S3, closing the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel in sequence, connecting a resin source to each resin channel, and applying pressure respectively, the injection pressure value being P2; S4, opening the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel in sequence, allowing the resin to enter the molding die from each resin channel and inject the woven composite material fan blade again for 10 to 15 minutes; S5, gradually increase the injection pressure of the glue inlet to P2, and close the glue outlet; S6, increasing the injection pressure of the first resin channel to P3; S7. The entire resin transfer molding process composite material forming system is heated up. When the system reaches the resin curing insulation temperature, the glue inlet, the first resin channel, the second resin channel, the third resin channel, the fourth resin channel, and the fifth resin channel are closed in sequence.

2. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: After step S7, the method further includes: S8. After the woven composite material fan blade is cured, take it out from the molding mold.

3. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The fiber volume fraction of the tenon is 50% to 52%, the fiber volume fraction of the transition zone is 52% to 62%, the fiber volume fraction of the leading edge of the blade is 60% to 62%, and the fiber volume fraction of the blade body is 58% to 60%.

4. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The injection temperature is 160-170°C.

5. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: Step S2 is controlled within 15 minutes.

6. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The whole process from step S2 to step S6 is controlled within 35 minutes.

7. The method for improving the yield of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The resin curing and heat preservation temperature is 180°C.

8. The method for improving the yield of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The injection pressure value is P0<P1<P2<P3.

9. The method for improving the yield rate of composite materials formed by resin transfer molding process according to claim 1, characterized in that: P0 is 0~0.5MPa, P1 is 0.6~0.8MPa, P2 is 0.9~1.1MPa, and P3 is 1.2~1.5MPa.

10. The method for improving the yield of composite materials formed by resin transfer molding process according to claim 1, characterized in that: The fracture energy G of the resin IC ≥1000J / m 2 .

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