Orthotropic carbon fiber reinforced cylindrical shell structure and processing method thereof

Abstract

The application relates to a kind of orthogonal right-angled carbon fiber reinforced cylinder shell structures and processing methods thereof, including cylinder shell body and the reinforcing rib structure located in the inner side of cylinder shell body, the cylinder shell body is aluminum alloy material, is integrally formed by spin extrusion process, the reinforcing rib structure is fixedly connected to the inner side of the cylinder shell body, including two rows of vertical ribs and the horizontal rib between the two rows of vertical ribs, each row of vertical rib includes multiple, is distributed along the circumference of cylinder shell body, the horizontal rib is carbon fiber reinforcing rib, is formed using carbon fiber prepreg winding process, the vertical rib is thermoplastic carbon fiber material, is formed by mould pressing process.The application can replace aluminum alloy rib with carbon fiber under the premise of guaranteeing the bearing performance of overall structure, realize the purpose of overall weight reduction;In the aspect of process processing, spin extrusion, laser welding and fiber winding are used, the precision is improved in the aspect of rib processing, and the processing method is easy to realize, has higher application and popularization value.

Description

Technical Field

[0001] The present invention relates to the technical field of manufacturing main load-bearing components of aerospace structures, and in particular to an orthogonal carbon fiber reinforced cylindrical shell structure and a processing method thereof. Background Art

[0002] Thin-walled cylindrical shell structures have high specific stiffness and high specific strength. In the field of aerospace, grid-reinforced cylindrical shell structures are widely used as the main connection and load-bearing structure. Under the action of compressive loads, instability is the main form of failure. During the rocket launch process, the thin-walled cylindrical shell structure is subjected to huge axial compressive loads due to overload, and is prone to buckling instability, which leads to structural failure. Therefore, the ultimate bearing capacity of the thin-walled cylindrical shell structure under axial compression conditions is a key assessment indicator in the design process of aerospace structures such as launch vehicles. Under axial compression conditions, the main failure mode of the reinforced cylindrical shell structure is buckling instability, including overall structural instability, local instability of the skin, local instability of the ribs, and plastic instability of the material.

[0003] In order to meet the strength and stiffness requirements of the components, the skin thickness or rib thickness of the cylindrical shell is usually increased, which leads to an increase in the weight of the component. At the same time, the existing forming methods of the cylindrical shell structure are usually casting, extrusion, machining and welding, but each process has certain disadvantages, such as low production precision and easy deformation during processing. In the fields of aviation launch vehicles, satellites, and spacecraft, grid-reinforced cylindrical shells are often used as connecting components, mainly to play a load-bearing role. In order to ensure its load-bearing performance, the skin thickness and reinforcement thickness have to be increased, resulting in a greater price for the grid-reinforced cylindrical shell of metal materials to meet the strength and stiffness requirements, thereby increasing the weight of the overall structure. With existing processing technology, high-precision machining is required in the later stage of forging to ensure the reinforcement accuracy of the product. After extrusion, the rib accuracy is still difficult to guarantee. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide an orthogonal carbon fiber reinforced cylindrical shell structure and a processing method thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] An orthogonal carbon fiber reinforced cylindrical shell structure includes a cylindrical shell body and a reinforcing rib structure located on the inner side of the cylindrical shell body. The cylindrical shell body is made of aluminum alloy and is integrally formed through a rotary extrusion process. The reinforcing rib structure is fixedly connected to the inner side of the cylindrical shell body and includes two rows of vertical ribs and transverse ribs located between the two rows of vertical ribs. Each row of the vertical ribs includes multiple ribs distributed along the circumference of the cylindrical shell body.

[0007] According to the above technical solution, preferably, the transverse ribs are carbon fiber reinforcement ribs, which are formed by a carbon fiber prepreg winding process.

[0008] According to the above technical solution, preferably, the vertical ribs are made of thermoplastic carbon fiber material and are formed by a molding process.

[0009] According to the above technical solution, preferably, the vertical ribs are fixedly connected to the inner side surface of the cylinder shell body by one or more methods of bonding, riveting, welding, and laser welding.

[0010] According to the above technical solution, preferably, the shell body includes a skin, an upper end frame and a lower end frame located at both ends of the skin, and the reinforcing rib structure is fixedly connected to the surface of the skin.

[0011] According to the above technical solution, preferably, the contact side of the vertical rib with the skin is an arc contact surface, and its inner radius is equal to the radius of the outer surface of the skin.

[0012] According to the above technical solution, preferably, the width of each row of the vertical ribs is unequal, and the two rows of the vertical ribs are arranged in a vertically symmetrical manner.

[0013] The present application also discloses a method for processing an orthogonal carbon fiber reinforced cylindrical shell structure, which is used to process the above-mentioned orthogonal carbon fiber reinforced cylindrical shell structure, comprising the following steps:

[0014] S1. The shell body is integrally formed by a rotary extrusion process;

[0015] S2. The vertical ribs are fixedly connected one by one to the inner surface of the shell body, and the horizontal ribs are reserved between the two rows of vertical ribs, with a spacing of the width of the horizontal ribs;

[0016] S3. Using fiber winding equipment to wind carbon fibers in the gap between the two rows of vertical ribs;

[0017] S4. Place the whole in a high-temperature curing furnace, cool it after curing, and remove the carbon fiber reinforced shell structure to complete the entire process.

[0018] According to the above technical solution, preferably, in step S2, the vertical ribs are fixedly connected one by one to the inner surface of the skin using a laser welding process, and the laser welding process includes:

[0019] Place the prefabricated vertical reinforcement in the fixture on the upper part of the fixture;

[0020] The fixing device applies pressure through a cylinder to make the vertical ribs fit tightly against the outer surface of the skin;

[0021] The laser irradiation side of the laser head is located on the inner surface of the skin. The laser power range is 700W-800W, the laser scanning speed is 10mm / s, and the laser light plate diameter is 5mm as the welding process parameters to complete the welding of the vertical ribs and the skin.

[0022] After completing the welding of one set of vertical ribs, the shell body is rotated by a certain distance and then the welding operation of the next set of vertical ribs is completed.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides an orthogonal carbon fiber reinforced thermoplastic composite grid-reinforced cylindrical shell structure, which can use carbon fibers instead of aluminum alloy ribs to achieve the purpose of overall weight reduction while ensuring the bearing performance of the overall structure. At the same time, in terms of process processing, unlike existing traditional processing methods, it adopts rotary extrusion, laser welding and fiber winding, which improves the precision of rib processing, and the processing method is easy to implement, with high application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a main structural schematic diagram of the present invention.

[0026] Figure 2 It is a schematic diagram of the main structure of the barrel shell body of the present invention.

[0027] Figure 3 It is a schematic diagram of the main structure of the reinforcing rib structure of the present invention.

[0028] Figure 4 It is a schematic diagram of the local structure of the connection between the skin and the reinforcing rib structure of the present invention.

[0029] Figure 5 It is a schematic diagram of the three-dimensional structure of the transverse rib part of the present invention.

[0030] Figure 6 It is a schematic diagram of the three-dimensional structure of the laser welding process of the present invention.

[0031] In the figure: 1. Upper end frame; 2. Skin; 3. Lower end frame; 4. Vertical rib a; 5. Horizontal rib; 6. Vertical rib b; 7. Laser welding equipment; 8. Robotic arm; 9. Laser head; 10. Fixing device. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and the best embodiment. Based on the embodiments of the invention, all other embodiments obtained by those skilled in the art without making any creative work shall fall within the scope of protection of the invention.

[0033] In the description of the invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the invention.

[0034] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "installed," "disposed," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0035] Example 1: As shown in the figure, the present invention discloses an orthogonal carbon fiber reinforced cylindrical shell structure, including a cylindrical shell body and a reinforcing rib structure located on the inner side of the cylindrical shell body. The cylindrical shell body is made of aluminum alloy and is integrally formed by a rotary extrusion process. The cylindrical shell body includes a skin 2, an upper end frame 1 and a lower end frame 3 located at both ends of the skin 2, and the reinforcing rib structure is fixedly connected to the surface of the skin 2.

[0036] The reinforcing rib structure includes two rows of vertical ribs and transverse ribs 5 located between the two rows of vertical ribs. Each row of the vertical ribs includes a plurality of ribs distributed along the circumference of the shell body. The vertical ribs are made of thermoplastic carbon fiber and are formed by a molding process. Two rows (i.e., vertical ribs a4 and vertical ribs b6) are evenly arranged near the upper end frame 1 and the lower end frame 3 on the shell body. The vertical ribs are fixedly connected to the inner side of the shell body by one or more methods including bonding, riveting, welding, and laser welding. Specifically, in this example, the side where the vertical ribs contact the skin 2 is an arc contact surface, and its inner radius R is equal to the radius R of the outer surface of the skin 2. The vertical ribs a4 and b6 are arranged in a symmetrical manner. In this example, it is preferred but not limited to that three thin vertical ribs are spaced between each thick vertical rib and they are evenly arranged. When applying actual products, the design and arrangement can be based on the specific stress conditions. In addition, the transverse ribs 5 are carbon fiber reinforcement ribs, which are formed using a carbon fiber prepreg winding process. Specifically, the transverse ribs 5 are formed using a 90° circumferential multi-layer winding method of prepreg. The width of the prepreg is consistent with the width of the transverse ribs 5, and the winding height is consistent with the height of the vertical ribs.

[0037] Example 2: This application also discloses a method for processing an orthogonal carbon fiber reinforced cylindrical shell structure, which is used to process the above-mentioned orthogonal carbon fiber reinforced cylindrical shell structure, comprising the following steps:

[0038] S1. The shell body is integrally formed by a rotary extrusion process;

[0039] S2. The vertical ribs are fixedly connected one by one to the inner surface of the shell body skin 2, and the two rows of the vertical ribs are reserved for the transverse ribs 5, with a spacing of the width of the transverse ribs 5;

[0040] S3. Install the cylindrical shell with welded vertical ribs on a fiber winding machine. Use the fiber winding machine to wind carbon fiber into the reserved gap between the two rows of vertical ribs. Specifically, in this example, T700-grade carbon fiber is used with epoxy resin, wound in a 90° circumferential direction. The transverse ribs 5 are left with a width of 3.5 mm. A single strand of yarn is used for winding, with a spread width of 3.5 mm.

[0041] S4. Finally, place the whole in a high-temperature curing furnace. The curing conditions are 80℃ / 2h and 100℃ for 6h. After curing, stop the furnace and cool it to below 40℃. Take out the reinforced tube to complete the whole process.

[0042] According to the above embodiment, preferably, in step S2, a laser welding process is used to fix the vertical ribs one by one to the inner surface of the skin 2. The laser welding equipment 7 includes a robot arm 8, a laser head 9 and a fixing device 10. The laser welding process includes:

[0043] S21. The prefabricated carbon fiber vertical ribs a4 and b6 are placed in the rectangular groove formed by the upper fixture 10. The fixture 10 has an automatic locking structure and axial lifting and boosting capabilities (cylinder boosting).

[0044] S22. The fixing device 10 applies pressure through the cylinder so that the vertical ribs a4 and b6 fit closely with the outer surface of the skin 2;

[0045] S23. The laser irradiation side of the laser head 9 is located on the inner surface of the skin 2. The laser power range is selected as 700W-800W, the laser scanning speed is 10mm / s, and the laser plate diameter is 5mm as the welding process parameters to complete the welding of the vertical ribs to the skin 2.

[0046] S24. After completing the welding of one set of vertical ribs, the shell body is rotated a certain distance and the welding operation of the next set of vertical ribs is completed.

[0047] The present invention discloses an orthogonal carbon fiber reinforced thermoplastic composite grid-reinforced cylindrical shell structure and its processing method. The outer skin and upper and lower end frames are integrally formed using an aluminum alloy spin-extrusion process. The vertical ribs are carbon fiber reinforcements formed using a carbon fiber molding process and laser welded to the outer skin. The transverse ribs are carbon fiber reinforcements formed using a carbon fiber prepreg winding process. The carbon fiber grid-reinforced cylindrical shell produced using the above processing method reduces the weight of the cylindrical shell while ensuring its strength and rigidity requirements, and reduces processing difficulty and cost.

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for processing an orthogonal carbon fiber reinforced cylindrical shell structure, which is used to process an orthogonal carbon fiber reinforced cylindrical shell structure, characterized in that: The orthogonal carbon fiber reinforced cylindrical shell structure comprises a cylindrical shell body and a reinforcing rib structure located on the inner side of the cylindrical shell body, wherein the cylindrical shell body is made of aluminum alloy and is integrally formed by a rotary extrusion process, and the reinforcing rib structure is fixedly connected to the inner side of the cylindrical shell body and comprises two rows of vertical ribs and transverse ribs (5) located between the two rows of vertical ribs, wherein each row of the vertical ribs comprises a plurality of ribs and is distributed along the circumference of the cylindrical shell body; The processing method includes the following steps: S1. The shell body is integrally formed by a rotary extrusion process; S2. The vertical ribs are fixedly connected one by one to the inner surface of the skin (2) of the shell body, and a position for the transverse ribs (5) is reserved between the two rows of the vertical ribs, and the spacing is the width of the transverse ribs (5); S3. Using fiber winding equipment to wind carbon fibers in the gap between the two rows of vertical ribs; S4. Place the whole in a curing oven, cool it after curing, and remove the carbon fiber reinforced shell structure to complete the entire process.

2. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 1, characterized in that: In step S2, the vertical ribs are fixedly connected one by one to the inner surface of the skin (2) using a laser welding process, and the laser welding process includes: Placing the prefabricated vertical reinforcement in a fixture on the upper portion of the fixing device (10); The fixing device (10) applies pressure through a cylinder to make the vertical ribs fit tightly against the outer surface of the skin (2); The laser irradiation side of the laser head (9) is located on the inner surface of the skin (2), and the laser power usage range of 700W-800W, the laser scanning speed of 10mm / s, and the laser light plate diameter of 5mm are selected as welding process parameters to complete the welding of the vertical ribs and the skin (2); After completing the welding of one set of vertical ribs, the shell body is rotated by a certain distance and then the welding operation of the next set of vertical ribs is completed.

3. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 1, characterized in that: The transverse ribs (5) are carbon fiber reinforcement ribs, formed by a carbon fiber prepreg winding process.

4. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 3, characterized in that: The vertical ribs are made of thermoplastic carbon fiber and are formed by a molding process.

5. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 4, characterized in that: The vertical ribs are fixedly connected to the inner side surface of the cylinder shell body by one or more methods of bonding, riveting, welding, and laser welding.

6. A method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to any one of claims 1 to 5, characterized in that: The shell body comprises a skin (2), an upper end frame (1) and a lower end frame (3) located at both ends of the skin (2), and the reinforcing rib structure is fixedly connected to the surface of the skin (2).

7. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 6, characterized in that: The contact side of the vertical rib and the skin (2) is an arc contact surface, the inner radius of which is equal to the radius of the outer surface of the skin (2).

8. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 1, characterized in that: The widths of the vertical ribs in each row are not equal.

9. The method for processing an orthogonal carbon fiber reinforced cylindrical shell structure according to claim 8, characterized in that: The two rows of vertical reinforcements are arranged in a vertically symmetrical manner.

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