Large-size complex cavity structure frame and assembly method thereof

Abstract

The invention provides a large-size complex cavity structure frame and an assembly method thereof, and solves the technical problem that in the structural design of an existing load subsystem, a large-size frame adopts a split structure combined with a CVI-SiC rivet welding process, and the rigidity of the frame is low after splicing and riveting. The left carbon fiber shell and the right carbon fiber shell are made of continuous carbon fiber cloth, and high radial strength is achieved; the area with large local bearing capacity is reinforced by taking the left cuboid box component and the right cuboid box component as vertical ribs and thickening; a plurality of lightening holes are formed in the left cuboid box components, the multiple layers of carbon fiber cloth wrapping the left cuboid box components, the right cuboid box components and the multiple layers of carbon fiber cloth wrapping the multiple right cuboid box components respectively, and the weight of the left ring frame and the weight of the right ring frame can be reduced.

Description

Technical Field

[0001] This invention relates to a method for forming large-size prefabricated frames, frames and their assembly methods, and specifically to a large-size complex cavity structure frame and its assembly method. Background Technology

[0002] C / SiC ceramic matrix composites have been widely used in aerospace, photovoltaic, semiconductor, and new energy vehicle fields due to their advantages such as light weight, high strength, low linear expansion, corrosion resistance, and low vacuum outgassing. In particular, the performance and reliability of C / SiC ceramic matrix composites have been successfully verified in satellite support structures used in the aerospace field, thanks to their lightweight characteristics (density 2.0 g / cm³). 3 (Weight reduction of more than 50%) can significantly reduce the weight of the support cylinder and other support structural components during the structural design of the load subsystem, providing conditions for the system to carry more instruments and equipment.

[0003] The frame structure serves as the mounting platform for the payload subsystem. In current mainstream high-resolution cameras and other payload systems, it acts as the equipment installation platform. Its structural characteristics typically include large size (2-3 meters in length, 1-2 meters in width, and 0.5-1.5 meters in height), complex cavities, thick walls, and fusion of metal composites. Its service environment is the space environment, with temperatures typically ranging from -50 to 150°C. To ensure the imaging quality and sharpness of high-resolution cameras, current high-resolution camera systems generally require the support frame to have a low coefficient of linear expansion and minimal deformation under gravity. Furthermore, due to their large size and weight, the frame components in currently mature titanium alloy and Invar metal solutions weigh approximately 300-600 kg per piece, significantly exceeding the system weight requirements. Using C / SiC ceramic matrix composite materials can achieve a weight reduction of over 50%. In addition, to improve the high rigidity of frame components, the prefabricated frame components are usually required to be integrally molded.

[0004] Current methods for fabricating frame structures using C / SiC ceramic matrix composites involve a split-structure design combined with CVI-SiC riveting and welding to assemble the internal components. The drawbacks of this method are: 1) When fabricating large-sized complex cavity structure frames using a split structure, a large number of molds need to be produced, resulting in high manufacturing costs and low deposition efficiency. 2) After the modular structure is assembled and riveted, the gaps between the parts are large, resulting in a lower frame stiffness than the integral structure, which cannot meet the usage requirements. 3) The prefabrication process of the split structure scheme has low material utilization and a long preparation cycle. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem of low frame stiffness after assembly and riveting in existing load subsystem structural designs where large-size frames are designed with a split structure and CVI-SiC riveting process. This invention provides a large-size complex cavity structure frame and its assembly method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A large-size complex cavity structure frame, characterized in that it includes a left ring frame, a right ring frame, multiple metal connecting plates, metal connecting bolts, and mating surface connecting bolts, wherein the lateral and longitudinal dimensions of the left ring frame and the right ring frame can reach 2m; The left and right ring frames are connected and contacted through mating surfaces. Adhesive is provided between the contact surfaces of the left and right ring frames, and they are connected by mating surface connecting bolts. The metal connecting plate is connected to the upper and lower end faces of the left and right ring frames at the joint position by metal connecting bolts.

[0007] Furthermore, the preparation method of the left and right ring frames is as follows: Step 1: Prepare left and right cuboid box components one by one by layering, cutting and folding carbon fiber cloth. Arrange the cuboid box components according to the internal structural requirements of the frame. Use carbon fiber bundles to sew together two adjacent left and two adjacent right cuboid box components to form a left multi-partition box structure and a right multi-partition box structure. Step 2: Using continuous carbon fiber cloth, wrap it layer by layer around the left and right multi-partition box-shaped structures respectively, and combine it with cutting and flanging to form square tube components with symmetrical polygonal structures as the left and right carbon fiber shells; Step 3: Use carbon fiber bundles to sew the left multi-partition box structure to the left carbon fiber shell to obtain the left ring frame prefabricated body; use carbon fiber bundles to sew the right multi-partition box structure to the right carbon fiber shell to obtain the right ring frame prefabricated body. Step 4: Prepare silicon carbide substrates on the left and right ring frame preforms using the CVI process to obtain the left and right ring frames.

[0008] Furthermore, step 1 also includes: Multiple weight-reduction holes are respectively opened on the left and right cuboid box components; Step 2 also includes: Multiple weight-reduction holes are made on the left and right carbon fiber shells respectively.

[0009] Furthermore, the wall thickness of the left carbon fiber outer shell and the right carbon fiber outer shell is 4mm to 10mm; The wall thickness of the left and right cuboid box components is 2 mm to 10 mm.

[0010] Furthermore, the adhesive is an epoxy resin structural adhesive with a layer thickness of 0.05mm-0.3mm.

[0011] An assembly method for a large-size complex cavity structure frame, characterized by the following steps: Step 1: Detect the outer dimensions of the left and right ring frames, establish machining datum, and adjust machining allowance; then machine the contact surfaces of the left and right ring frames to ensure that the flatness of the contact surfaces is <0.1mm; drill screw holes on the contact surfaces of the left and right ring frames. Step 2: Apply adhesive to the contact surfaces of the left and right ring frames respectively, place the left and right ring frames on the same reference plane, adjust the deviation of the left and right ring frames, and adjust the left and right ring frames to be consistent in the width and height directions; Step 3: Connect the mating surface bolts into the screw holes on the contact surfaces of the left and right ring frames to connect the left and right ring frames, and place them at room temperature to cure for 48-50 hours. Step 4: Make bolt mounting holes on the upper and lower surfaces of the left and right ring frames at the joint position, and use metal connecting bolts to set the metal connecting plates on the upper and lower surfaces of the left and right ring frames at the joint position respectively. Step 5: Measure the flatness and parallelism of the surface of the metal connecting plate using a dial indicator. If it does not meet the requirements, use a CNC machining program to finely machine the surface of the metal connecting plate until it meets the requirements. Clean the surface of any debris and complete the assembly of the large-size complex cavity integral frame prefabricated frame.

[0012] Furthermore, in step 3, adhesive is applied to the connecting bolts on the mating surfaces.

[0013] Furthermore, in step 4, adhesive is applied to the metal connecting plate, and the side with adhesive is respectively placed on the upper and lower end surfaces of the left and right ring frames at the joint position.

[0014] Furthermore, step 4, after installing the metal connecting plate, also includes: Place the left and right ring frames at room temperature and allow them to cure for 48-50 hours.

[0015] The beneficial effects of this invention are: 1. This invention provides a large-size complex cavity structure frame, which uses continuous carbon fiber cloth to prepare the left and right carbon fiber shells, resulting in high radial strength. In areas with large local loads, the left and right cuboid box components are reinforced by thickening them as vertical ribs. Multiple weight-reducing holes are opened on the left cuboid box component, the multi-layer carbon fiber cloth covering multiple left cuboid box components, the right cuboid box component, and the multi-layer carbon fiber cloth covering multiple right cuboid box components, which can reduce the weight of the left and right ring frames. Furthermore, with the reinforcement of the vertical ribs, the horizontal and vertical dimensions of the prepared left and right ring frames can reach 2m.

[0016] 2. This invention provides a large-size complex cavity structure frame. The left and right ring frames are connected by adhesive, connecting bolts, metal connecting plates, and connecting bolts, which can improve the connection strength at the connection point. At the same time, the resulting large-size complex cavity structure frame can reach a size of 4m, which can meet the requirements of payload subsystems in the aerospace field for large-size frames.

[0017] 3. This invention provides an assembly method for a large-size complex cavity structure frame, which has the advantages of simple operation and high assembly accuracy. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the left multi-partition box-shaped structure and the right multi-partition box-shaped structure in an embodiment of a large-size complex cavity structure frame of the present invention; (a) is a left-side multi-partition box-type structure, and (b) is a right-side multi-partition box-type structure. Figure 2 This is a schematic diagram of the left and right carbon fiber shells in an embodiment of a large-size complex cavity structure frame of the present invention; (a) is the left carbon fiber shell, and (b) is the right carbon fiber shell; Figure 3 This is a partial structural diagram of a large-size complex cavity structure frame embodiment, in which a left multi-partition box-shaped structure is obtained by continuously winding carbon fiber cloth layer by layer to obtain a left carbon fiber shell. Figure 4 This is a schematic diagram of the left and right ring frames in an embodiment of a large-size complex cavity structure frame of the present invention; (a) is the left ring frame, (b) is the right ring frame; Figure 5 This is a schematic diagram of an embodiment of a large-size complex cavity structure frame according to the present invention; Figure 6 This is a schematic diagram of the installation of connecting bolts in step 3 of an embodiment of the assembly method of a large-size complex cavity structure frame of the present invention.

[0019] The attached figures are labeled as follows: 1-Left ring frame, 101-Left carbon fiber shell, 102-Left multi-partition box structure, 102-1~102-7-Left cuboid box components; 2-Right ring frame, 201-Right carbon fiber shell, 202-Right multi-partition box structure; 3-Metal connecting plate; 4-Mating surface connecting bolt; 5-Metal part connecting bolt. Detailed Implementation

[0020] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and 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.

[0021] This invention provides a framework for a large-sized complex cavity structure, which first involves fabricating a left ring frame 1 and a right ring frame 2, including the following steps: Step 1: Lay carbon fiber fabric in layers to prepare a left cuboid box component and a right cuboid box component, and arrange them in a symmetrical polygonal pattern. Use carbon fiber bundles to sew together adjacent left cuboid box components and adjacent right cuboid box components. Cover the sewn left and right cuboid box components with multiple layers of carbon fiber fabric to form a left multi-partition box structure 102 and a right multi-partition box structure 202. The left multi-partition box structure 102 and the right multi-partition box structure 202 serve as reinforcing vertical ribs. In this embodiment, using carbon fiber bundles to sew together adjacent left and right cuboid box components significantly improves the stiffness and strength of the components compared to using pin connections.

[0022] The wall thickness of the left and right cuboid box components is 2 mm to 10 mm; for example... Figure 1 As shown, (a) is a left multi-partition box structure, and (b) is a right multi-partition box structure.

[0023] To further reduce the overall weight of the components, multiple weight-reduction holes are made on the left cuboid box component, the multi-layer carbon fiber cloth covering the left cuboid box components, the right cuboid box component, and the multi-layer carbon fiber cloth covering the right cuboid box components.

[0024] Step 2: Using continuous carbon fiber fabric, wrap it layer by layer around the left multi-partition box structure 102 and the right multi-partition box structure 202, respectively, and then cut and fold it to form symmetrical polygonal square tube components as the left carbon fiber outer shell 101 and the right carbon fiber outer shell 201. The left carbon fiber outer shell 101 and the right carbon fiber outer shell 201 have the same structure, such as... Figure 2As shown, (a) is the left carbon fiber shell, and (b) is the right carbon fiber shell; the wall thickness of the left carbon fiber shell 101 and the right carbon fiber shell 201 is 4mm~10mm. Figure 3 As shown in the diagram, the lines represent the direction of the continuous carbon fiber fabric. Figure 3 102-1 to 102-7 in the middle all represent the left cuboid box components. The left multi-partition box structure 102 and the right multi-partition box structure 202 serve as reinforcing vertical ribs to strengthen the left carbon fiber shell 101 and the right carbon fiber shell 201.

[0025] Multiple weight-reducing holes are made on the left carbon fiber shell 101 and the right carbon fiber shell 201 respectively, which can reduce the overall weight.

[0026] Step 3: Use carbon fiber bundles to sew the left multi-partition box structure 102 to the left carbon fiber shell 101 to obtain the left ring frame; use carbon fiber bundles to sew the right multi-partition box structure 202 to the right carbon fiber shell 201 to obtain the right ring frame. Step 4: Using the CVI process, silicon carbide substrates are grown on the left and right ring frames to obtain left ring frame 1 and right ring frame 2, which are the prefabricated large-size complex cavity structure, such as... Figure 4 As shown, (a) is the left ring frame and (b) is the right ring frame.

[0027] The left ring frame 1 and the right ring frame 2 are C / SiC monolithic ceramic matrix composite components, characterized by their light weight and high strength. Through assembly, they can form large-size (3-meter level) C / SiC monolithic ceramic matrix composite frames.

[0028] Because the left ring frame 1 and right ring frame 2 in this embodiment are relatively lightweight, the problem of deformation due to their own weight during the high-temperature environment of the CVI process can be overcome. Since the left multi-partition box structure 102 and right multi-partition box structure 202 serve as reinforcing vertical ribs, the horizontal and vertical dimensions of the prepared left and right ring frames can reach 2m under the reinforcement of these vertical ribs.

[0029] After forming the left ring frame 1 and the right ring frame 2, as follows Figure 5 As shown, this embodiment of a large-size complex cavity structure frame also includes a metal connecting plate 3, metal connecting bolts 5, and mating surface connecting bolts 4; the left ring frame 1 and the right ring frame 2 are connected by the metal connecting bolts 5 and the mating surface connecting bolts 4, and adhesive is used to assist in the bonding; specifically: One of the outer surfaces of the left ring frame 1 and the right ring frame 2 of the same size is used as the contact surface. An epoxy resin structural adhesive with a thickness of 0.05mm-0.1mm is applied between the contact surfaces of the left ring frame 1 and the right ring frame 2. They are connected by mating bolts 4. The left ring frame 1 and the right ring frame 2 are symmetrical about the contact surfaces. The metal connecting plate 3 is connected to the symmetrical polygonal side surfaces of the left ring frame 1 and the right ring frame 2 by metal connecting bolts 5.

[0030] This embodiment also provides an assembly method for a large-size complex cavity integral frame prefabricated frame. Before assembly, after the C / SiC ceramic matrix composite frame is deposited to the required density, the contact surfaces of the left ring frame 1 and the right ring frame 2 are machined using a CNC machine tool. The main purpose of machining is to remove excess material and improve the flatness of the contact surfaces. To ensure the flatness of the contact surfaces of the left ring frame 1 and the right ring frame 2, the contact surfaces need to be machined. After machining, the left ring frame 1 and the right ring frame 2 are cleaned and dried. Ultrasonic cleaning equipment is used, along with deionized water, to ultrasonically clean the left ring frame 1 and the right ring frame 2 for 6-12 hours. After ultrasonic cleaning, the left ring frame 1 and the right ring frame 2 are placed in an oven at 60-200℃ to dry for 4-12 hours, and then the following steps are performed: Step 1: Use a dial indicator on a machine tool to check the external dimensions of the left ring frame 1 and the right ring frame 2. Machin the contact surfaces of the left ring frame 1 and the right ring frame 2 according to the CNC machining program to make the flatness of the contact surfaces <0.1mm. Make screw holes on the contact surfaces of the left ring frame 1 and the right ring frame 2.

[0031] Step 2: Apply adhesive to the contact surfaces of the left ring frame 1 and the right ring frame 2 respectively. Place the left ring frame 1 and the right ring frame 2 on the same reference plane. Use tooling to adjust the deviation of the left ring frame 1 and the right ring frame 2 to make the left ring frame 1 and the right ring frame 2 symmetrical in the width direction. Step 3, as follows Figure 6 As shown, epoxy resin structural adhesive is applied to the mating surface connecting bolt 4. The mating surface connecting bolt 4 is connected to the screw holes on the contact surface of the left ring frame 1 and the right ring frame 2 to achieve the connection between the left ring frame 1 and the right ring frame 2. It is then placed in a room temperature environment and cured for 48h-50h. Step 4: Make bolt mounting holes on the upper and lower surfaces of the left ring frame 1 and the right ring frame 2 at the docking position. Apply epoxy resin structural adhesive to the metal connecting plate 3, and place the side with epoxy resin structural adhesive on the upper and lower surfaces of the left ring frame 1 and the right ring frame 2 at the docking position respectively, and fix them together with metal connecting bolts.

[0032] Place the left ring frame 1 and the right ring frame 2 in a room temperature environment and cure for 48-50 hours.

[0033] Step 5: Measure the flatness and parallelism of the surface of the metal connecting plate 3 using a dial indicator. If it does not meet the requirements, use a CNC machining program to finely machine the surface of the metal connecting plate 3 until it meets the requirements; and clean the surface of any debris to complete the assembly of the large-size complex cavity integral frame prefabricated frame.

[0034] The large-size complex cavity integral prefabricated frame obtained in this embodiment has multiple connection points on the upper and lower surfaces during use to connect high-resolution camera related equipment. To ensure the connection strength at the connection points and avoid the phenomenon that the C / SiC ceramic matrix composite material frame may be crushed or torn at the connection points during equipment use, and to achieve the planar accuracy of the equipment mounting surface, metal pads can be set on the upper and lower surfaces of the frame.

[0035] In this embodiment, the frame size of the large-size complex cavity structure can reach 4m, which can meet the requirements of the payload subsystem in the aerospace field for large-size frames.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A large-size complex cavity structure frame, characterized in that, It includes a left ring frame (1), a right ring frame (2), multiple metal connecting plates (3), metal connecting bolts (5), and mating surface connecting bolts (4). The horizontal and vertical dimensions of the left ring frame (1) and the right ring frame (2) can reach 2m. The left ring frame (1) and the right ring frame (2) are in contact and connected through a mating surface. An adhesive is provided between the contact surfaces of the left ring frame (1) and the right ring frame (2), and they are connected by a mating surface connecting bolt (4). The metal connecting plate (3) is connected to the upper and lower end faces of the left ring frame (1) and the right ring frame (2) at the docking position by metal connecting bolts (5).

2. The large-size complex cavity structure frame according to claim 1, characterized in that, The preparation method of the left ring frame (1) and the right ring frame (2) is as follows: Step 1: The carbon fiber cloth is layered, cut, and folded to prepare the left cuboid box component and the right cuboid box component one by one. The cuboid box components are arranged according to the internal structural requirements of the frame. The two adjacent left cuboid box components and the two adjacent right cuboid box components are sewn together with carbon fiber bundles to form the left multi-partition box structure (102) and the right multi-partition box structure (202). Step 2: Using continuous carbon fiber cloth, wrap it layer by layer around the left multi-partition box structure (102) and the right multi-partition box structure (202), and cut and fold the edges to form square tube components with symmetrical polygonal structures as the left carbon fiber shell (101) and the right carbon fiber shell (201). Step 3: Use carbon fiber bundles to sew the left multi-partition box structure (102) to the left carbon fiber shell (101) to obtain the left ring frame preform; use carbon fiber bundles to sew the right multi-partition box structure (202) to the right carbon fiber shell (201) to obtain the right ring frame preform. Step 4: Prepare silicon carbide substrates on the left ring frame preform and the right ring frame preform using CVI process to obtain the left ring frame (1) and the right ring frame (2).

3. The large-size complex cavity structure frame according to claim 2, characterized in that, Step 1 also includes: Multiple weight-reduction holes are respectively opened on the left and right cuboid box components; Step 2 also includes: Multiple weight-reduction holes are made on the left carbon fiber shell (101) and the right carbon fiber shell (201).

4. The large-size complex cavity structure frame according to claim 1, characterized in that, The wall thickness of the left carbon fiber shell (101) and the right carbon fiber shell (201) is 4mm to 10mm; The wall thickness of the left and right cuboid box components is 2 mm to 10 mm.

5. The large-size complex cavity structure frame according to claim 4, characterized in that, The adhesive is an epoxy resin structural adhesive with a layer thickness of 0.05mm-0.3mm.

6. A method for assembling a large-size complex cavity structure frame as described in claim 4 or 5, characterized in that, Includes the following steps: Step 1: Detect the outer dimensions of the left ring frame (1) and the right ring frame (2), establish the machining datum, and adjust the machining allowance; then machine the contact surfaces of the left ring frame (1) and the right ring frame (2) to make the flatness of the contact surfaces < 0.1mm; open screw holes on the contact surfaces of the left ring frame (1) and the right ring frame (2); Step 2: Apply adhesive to the contact surfaces of the left ring frame (1) and the right ring frame (2), place the left ring frame (1) and the right ring frame (2) on the same reference plane, adjust the deviation of the left ring frame (1) and the right ring frame (2), and adjust the left ring frame (1) and the right ring frame (2) to be consistent in the width and height directions; Step 3: Connect the mating surface connecting bolts (4) into the screw holes on the contact surfaces of the left ring frame (1) and the right ring frame (2) to achieve the connection between the left ring frame (1) and the right ring frame (2), and place them in a room temperature environment to cure for 48h-50h. Step 4: Make bolt mounting holes on the upper and lower surfaces of the left ring frame (1) and right ring frame (2) at the docking position, and use metal connecting bolts (5) to set the metal connecting plate (3) on the upper and lower surfaces of the left ring frame (1) and right ring frame (2) at the docking position respectively. Step 5: Measure the flatness and parallelism of the surface of the metal connecting plate (3) using a dial indicator. If it does not meet the requirements, use a CNC machining program to finely machine the surface of the metal connecting plate (3) until it meets the requirements. Clean the surface of any debris and complete the assembly of the large-size complex cavity integral frame prefabricated frame.

7. The assembly method of a large-size complex cavity structure frame according to claim 6, characterized in that, In step 3, adhesive is applied to the mating surface connecting bolt (4).

8. The assembly method of a large-size complex cavity structure frame according to claim 6, characterized in that, In step 4, adhesive is applied to the metal connecting plate (3), and the side with adhesive is respectively placed on the upper and lower end surfaces of the left ring frame (1) and the right ring frame (2) at the docking position.

9. The assembly method of a large-size complex cavity structure frame according to claim 8, characterized in that, Step 4, after installing the metal connecting plate (3), also includes: Place the left ring frame (1) and the right ring frame (2) in a normal temperature environment and cure for 48 h - 50 h.

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