A method for manufacturing a reflector and the reflector

Abstract

The application aims to provide a preparation method of a reflector and the reflector. The preparation method of the reflector provided by the application adopts a metal transfer method to fix a metal reflecting surface on a reflecting panel, adopts a sub-block paving layer to realize the preparation of the reflecting panel, and the whole reflector is prepared by using the same composite material, so that various precision problems caused by the mismatch of material thermal expansion are effectively avoided.

Description

Technical Field

[0001] This invention relates to the technical field of reflectors, and more particularly to a method for manufacturing a reflector and the reflector itself. Background Technology

[0002] Currently, the basic structure of lightweight solid-surface reflectors used for microwave communication and observation consists of an aluminum honeycomb layer sandwiched between two composite material skins (front and rear skins). The aluminum honeycomb is a lightweight structural material sandwiched between the two skin layers, utilizing the in-plane stiffness of the front and rear skins to form a structure with high bending stiffness, known as a honeycomb core panel. The side of the front skin that does not contact the aluminum honeycomb serves as the electromagnetic wave reflecting surface; the closer its geometry is to the required geometry, the higher the accuracy and the higher the applicable radio frequency.

[0003] As mentioned earlier, the basic structure of existing lightweight solid-surface reflectors consists of an aluminum honeycomb layer sandwiched between two layers of carbon fiber composite skin. This makes it difficult to achieve or maintain a high level of surface accuracy in the reflective surface, thus failing to meet the increasingly higher electromagnetic wave frequencies required by modern space reflectors. The main reasons for the difficulty in achieving and maintaining high surface accuracy in such lightweight solid-surface reflectors are as follows:

[0004] 1) The coefficient of thermal expansion of aluminum is much higher than that of carbon fiber composite materials. Due to the periodic changes in the temperature of the satellite in orbit and the large temperature gradient caused by the radiation of the whole satellite, the thermal expansion and contraction of aluminum honeycomb can easily cause a large change in the geometry of the reflector, making it difficult to maintain the high precision of the reflector in orbit.

[0005] 2) Due to process limitations, it is difficult to make the height of aluminum honeycomb high, resulting in a smaller distance between the front and rear skins. Consequently, the overall rigidity of the reflector is low, making it prone to deformation and affecting the accuracy of the reflective surface.

[0006] 3) The process of machining aluminum honeycomb into curved surfaces inevitably results in residual elastic deformation and residual stress. After the reflector is finished, these residual elastic deformations and residual stresses will cause deformation of the reflective surface, reducing the accuracy of the surface profile.

[0007] 4) The front and rear skins are two curved surfaces. The existing production process uses carbon fiber composite material as an integral layer during the forming of the front and rear skins. This is not conducive to the low thermal expansion design of the layer, and the coefficient of thermal expansion varies greatly in different parts, which reduces the maintainability of the reflector's on-orbit accuracy.

[0008] For high-frequency radio wave reflectors, metal plating is required on the surface of the composite material to ensure their operating efficiency. Traditional reflector manufacturing processes involve first preparing the entire composite material structure, and then using vacuum plating or ion plating to complete the metal coating. Both vacuum plating and ion plating require a vacuum chamber, and due to limitations in chamber size and cost, large reflectors often cannot be metal-plated. Another problem with vacuum plating or ion plating is the poor adhesion between the coating and the composite material, making it prone to peeling off, and the lack of secondary finishing capabilities. Summary of the Invention

[0009] To overcome the aforementioned technical deficiencies, the present invention aims to provide a method for fabricating a reflector and the reflector itself. The method for fabricating a reflector provided by the present invention employs a metal transfer method to fix a metal reflective surface on a reflective panel, uses sub-block layup to fabricate the reflective panel, and uses the same composite material for the entire reflector, thus effectively avoiding various precision problems caused by material thermal expansion mismatch.

[0010] The present invention provides a method for manufacturing a reflector, comprising the following steps: preparing a curing mold for a reflective panel; forming a metal layer on the curing mold; forming a reflective panel on the metal layer using a sub-block layup method; preparing a composite material mesh using a symmetrical balanced layup method; assembling the composite material mesh onto the reflective panel; assembling a reinforcing structure on the composite material mesh to obtain the reflector, wherein the reflective panel, the composite material mesh, and the reinforcing structure are all made of the same carbon fiber composite prepreg.

[0011] Preferably, in the method for preparing the reflector, the geometric shape of the working surface of the curing mold of the reflective panel is calculated using an iterative accuracy compensation method.

[0012] Preferably, in the method for preparing the reflector, the reinforcing structure is a T-shaped structure, the T-shaped structure includes a web and a rear end plate connected to the web, the web is connected to the composite material mesh, and the rear end plate is composed of one or more composite material panels.

[0013] Preferably, in the method for preparing the reflector, the front end face of the web is connected to the composite material mesh, the geometry of the front end face is consistent with the geometry of the surface of the composite material mesh, and the rear end plate of the reinforcing structure is prepared by a sub-block layup method.

[0014] Preferably, in the method for preparing the reflector, the step of assembling the composite material mesh onto the reflective panel includes: laying the composite material mesh on the reflective panel using a symmetrical balanced layup method; co-curing the reflective panel and the composite material mesh; and assembling the composite material mesh onto the reflective panel through co-curing.

[0015] Preferably, in the method for preparing the reflector, the step of assembling the composite material mesh onto the reflective panel includes: preparing the reflective panel by sub-block layup and curing it; preparing the composite material mesh by symmetrical balanced layup and curing it; and bonding the composite material to the reflective panel by adhesive bonding.

[0016] Preferably, in the method for manufacturing the reflector, the iterative accuracy compensation method includes the following steps: Step 11: Establishing an initial finite element model of the curing mold and the reflector panel based on the geometry of the target reflector panel, wherein the reflector panel is placed in the curing mold; Step 12: Determining the temperature difference ΔT between the curing temperature of the reflector panel material and the assembly temperature of the reflector; Step 13: Cooling ΔT to cause thermal deformation of the initial finite element model; Step 14: Extracting the geometry and stress distribution of the cured reflector panel from the thermally deformed finite element model; Step 15: Obtaining the geometry of the cured reflector panel based on the extracted geometry and stress distribution; Step 16: Comparing the geometry of the cured reflector panel obtained in Step 15 with the geometry of the target reflector panel to obtain a geometric difference; Step 17: Compensating the geometry of the curing mold based on the geometric difference to obtain a compensated geometry of the curing mold.

[0017] Preferably, in the method for preparing the reflector, step 17 further includes setting a threshold and comparing the geometric difference with the threshold; when the geometric difference is less than or equal to the threshold, preparing a curing mold for the reflective panel according to the geometry of the compensated curing mold; when the geometric difference is greater than the threshold, establishing a one-element finite element model of the curing mold and the reflective panel according to the geometry of the compensated curing mold, wherein the reflective panel is placed in the curing mold, and repeating steps 12-17.

[0018] Preferably, in the method for preparing the reflector, the step of laying up the sub-blocks includes: dividing each layer of the composite laminate into multiple sub-blocks according to the required geometry of the composite laminate; cutting the prepreg to obtain the sub-blocks according to the geometry of the sub-blocks; and splicing and laying up the sub-blocks to obtain the required composite laminate.

[0019] Another aspect of the present invention provides a reflector comprising a reflective panel, a metal layer fixed to the reflective surface of the reflective panel, and a composite material mesh fixed to the reflective panel on a surface opposite to the reflective surface, wherein the reflective panel further comprises a reinforcing structure connected to the composite material mesh, the reflective panel being composed of a plurality of sub-blocks, the composite material mesh being composed of a plurality of symmetrically balanced layups, and the reflective panel, the composite material mesh, and the reinforcing structure being prepared from the same carbon fiber composite prepreg.

[0020] Preferably, in the reflector, the reinforcing structure is a T-shaped structure, the T-shaped structure includes a web and a rear end plate connected to the web, the web is connected to the composite material mesh, and the rear end plate is composed of one or more composite material panels.

[0021] Preferably, in the reflector, the front end face of the web is connected to the composite material mesh, and the geometry of the front end face is consistent with the geometry of the surface of the composite material mesh.

[0022] Preferably, in the reflector, the reflective panel comprises multiple quasi-isotropic plies, each ply consisting of multiple sub-blocks, and the boundary lines between the sub-blocks of adjacent layers do not coincide.

[0023] Compared with existing technologies, the above technical solution has the following advantages:

[0024] 1. Due to the very small residual stress generated during its manufacturing process, the reflector's surface geometry is very stable.

[0025] 2. The overall structure is made of a single structural material, which avoids precision problems caused by mismatch in thermal expansion of the materials.

[0026] 3. The structure adopts a balanced, symmetrical and quasi-zero thermal expansion layup, which almost completely avoids thermal deformation caused by on-orbit thermal load.

[0027] 4. The metal layer fabrication is not constrained by the size of equipment such as vacuum tanks, and large-diameter reflectors can be fabricated.

[0028] 5. The reflective surface possesses extremely high geometric precision and a very dense metal layer. High-precision grinding and polishing can be performed in the final stage of fabrication to further improve the reflector's accuracy. It is suitable for very high electromagnetic wave frequencies and can be used in the terahertz and even far-infrared bands. Attached Figure Description

[0029] Figure 1 A schematic diagram of the reflective panel layup structure of a reflector conforming to a preferred embodiment of the present invention;

[0030] Figure 2A schematic diagram of the structure of the reflector panel of a reflector conforming to a preferred embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the composite material mesh structure of a reflector conforming to a preferred embodiment of the present invention;

[0032] Figure 4 A schematic diagram of the enhanced structure of the reflector according to a preferred embodiment of the present invention. Detailed Implementation

[0033] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0034] To overcome the shortcomings of existing lightweight solid-surface reflectors, where the manufacturing process often results in a significant discrepancy between the reflected shape and the desired geometry, leading to insufficient reflector accuracy, this invention proposes a reflector manufacturing method, specifically including the following steps:

[0035] Step 1: Prepare the curing mold for the reflective panel;

[0036] Step 2: Form a metal layer on the curing mold;

[0037] Step 3: Form a reflective panel on the metal layer using a sub-block layup method;

[0038] Step 4: Prepare the composite material mesh using a symmetrical balanced layup method;

[0039] Step 5: Assemble the composite material mesh onto the reflective panel;

[0040] Step 6: Assemble the reinforcing structure on the composite material mesh to prepare the reflector.

[0041] A preferred method for sub-block layup involves dividing each layer of the composite laminate into multiple sub-blocks based on the required geometry. Prepreg is then cut according to the geometry of each sub-block to obtain corresponding composite material sub-blocks. These sub-blocks are then spliced ​​and laid up according to a specific pattern to obtain the desired composite laminate structure. Preferably, the boundary lines between adjacent sub-blocks do not coincide to ensure sufficient strength in the resulting composite laminate structure (the boundary lines between adjacent sub-blocks may coincide under special circumstances, provided the strength requirement is met). Sub-block layup allows for precise control of the fiber orientation of each layer at any point on the entire curved surface, ensuring symmetry, balance, and zero thermal expansion at any point. Sub-block layup is fundamental to ensuring that the thermal expansion coefficient of the entire reflective panel is zero.

[0042] Furthermore, in this embodiment, the metal layer is bonded to the composite material reflective panel via a metal transfer method. Preferably, the metal transfer process involves first spraying or electroplating the metal layer onto the mold surface, followed by layup and curing of the composite material. During demolding, the metal is transferred from the mold to the composite material. The difference between metal transfer and vacuum plating or ion plating is that it does not require closed equipment such as vacuum tanks, avoiding limitations on equipment size and allowing for the fabrication of large-sized reflectors. Another advantage of the metal transfer method is that it produces a dense metal layer with good adhesion to the composite material and allows for a wide range of selectable metal layer thicknesses.

[0043] In some embodiments, during the preparation of the curing mold for the reflective panel, an iterative accuracy compensation method is used to calculate the geometry of the working surface of the curing mold. In this embodiment, the iterative accuracy compensation method fully considers the possible deformation of the reflective panel during the curing process and under temperature changes, compensating for any possible geometric changes in the reflective panel onto the curing mold. This results in a compensated geometry of the curing mold. The reflective panel cured using this geometry as the working surface has a geometry that is completely consistent with the required geometry of the reflective panel. When assembled on the assembly mold, there will be no residual stress, resulting in a reflector with higher working accuracy.

[0044] Preferably, the iterative accuracy compensation method mentioned in the above embodiments may include the following steps:

[0045] S11: Based on the geometry of the target reflective panel, establish an initial finite element model of the curing mold and the reflective panel, wherein the reflective panel is placed in the curing mold;

[0046] S12: Determine the temperature difference ΔT between the curing temperature of the reflector panel material and the assembly temperature of the reflector;

[0047] S13: Cooling ΔT causes thermal deformation of the initial finite element model;

[0048] S14: Extract the geometry and stress distribution of the cured reflective panel from the finite element model after thermal deformation;

[0049] S15: Obtain the geometry of the cured reflective panel based on the extracted geometry and stress distribution of the cured reflective panel;

[0050] S16: Compare the geometry of the cured reflective panel obtained in step 15 with the geometry of the target reflective panel to obtain the geometric difference.

[0051] S17: Based on the geometric difference, compensate the geometry of the curing mold to obtain the compensated geometry of the curing mold.

[0052] Preferably, the curing mold of the reflective panel can be subjected to multiple iterations of precision compensation as described above, so that the geometric difference between the cured reflective panel and the target reflective panel continuously approaches infinitesimal, thereby meeting the requirement of improving the working accuracy of the reflector in practical applications. Specifically, step 17 above may further include the following steps:

[0053] Step 101: Set a threshold value and compare the geometric difference value with the threshold value.

[0054] Step 102: When the geometric difference is less than or equal to the threshold, prepare a curing mold for the reflective panel according to the geometry of the compensated curing mold;

[0055] Step 103: When the geometric difference is greater than the threshold, based on the geometry of the compensated curing mold, establish a one-element finite element model of the curing mold and the reflective panel, wherein the reflective panel is placed in the curing mold.

[0056] Step 104: Repeat steps 12-17.

[0057] The threshold value in this embodiment can be determined according to actual application requirements. The curing mold obtained according to the method of this embodiment is applied to the preparation of the reflective panel. Since the deformation of the reflective panel and the curing mold due to temperature changes during the curing process is fully considered, the difference in geometry between the prepared reflective panel and the target reflective panel can be reduced, thereby significantly improving the working accuracy of the prepared reflector.

[0058] In some embodiments, the reinforcing structure in the reflector is a T-shaped structure, including a web and a rear end plate connected to the web, the web being connected to the composite mesh. Preferably, the rear end plate is also prepared using a sub-block layup method. Preferably, the distance between the rear end plate of the T-shaped reinforcing structure and the composite mesh is as large as possible; the larger this distance, the greater the stiffness and stability of the entire reflector. Preferably, the rear end plate of the T-shaped reinforcing structure is optional depending on design requirements. Preferably, the rear end plate can be composed of one or more continuous surfaces; more preferably, the rear end plate can be a curved surface, a plane, a continuous surface formed by multiple planes, or a combination of planes and curved surfaces. These surfaces can be closed or porous.

[0059] In some embodiments, the assembly method of the composite material mesh and the reflective panel may include the following approaches:

[0060] Method 1: A composite material mesh is laid on the reflective panel using a symmetrical and balanced method; the reflective panel and the composite material mesh are co-cured; after such co-curing, the composite material mesh is assembled onto the reflective panel.

[0061] Method 2: The reflective panel is prepared by sub-block layup and then cured; the composite material mesh is prepared by symmetrical balanced layup and then cured; and then the composite material and the reflective panel are bonded together by adhesive bonding.

[0062] In this embodiment, the composite material mesh can be a mesh structure composed of triangles or a mesh structure composed of other suitable shapes, which can be determined according to the needs of the actual application.

[0063] In another aspect, the present invention provides a reflector that can be prepared by the above-described reflector preparation method, and specifically includes the following structure:

[0064] -Reflective panel 100

[0065] See Figure 1 The reflective panel 100 is composed of multiple sub-blocks. For example, the reflective panel 100 may include multiple quasi-isotropic plies, such as 6, 8, 12, 16, etc., all the number of layers that can satisfy symmetrical and balanced plies, and each ply is composed of multiple sub-blocks, for example... Figure 1 As shown. Preferably, the boundary lines between adjacent sub-blocks in the reflective panel 100 do not coincide. However, it should be noted that, under certain circumstances, the boundary lines between adjacent sub-blocks may coincide, provided that the strength requirements are met. The specific layup method and the specific number of layup layers of the sub-blocks in this embodiment can be designed according to actual application requirements without departing from the overall inventive concept of this invention.

[0066] -Metal layer 101

[0067] The metal layer 101 is fixed to the reflective surface of the reflective panel 100 to realize the reflective function of the reflector.

[0068] -Composite Materials Network 200

[0069] The composite material mesh 200 is fixed to the surface of the reflective panel 100 opposite to the reflective surface. Preferably, the composite material mesh 200 is a composite material mesh with gradually varying stiffness. Preferably, the layup of the composite material mesh 200 can also be selected from any number of layup layers that satisfy symmetry balance. Preferably, see [link to relevant documentation]. Figure 2The composite material mesh 200 can be a mesh structure composed of triangles or any other shape, which can be determined according to the needs of the actual application.

[0070] -Reinforced structure 300

[0071] The reinforcing structure is fixed to the composite material mesh. Preferably, see [link to relevant documentation]. Figure 3 The reinforcing structure is a T-shaped structure, comprising a web 301 and a rear end plate 302 connected to the web 301, wherein the web 301 is connected to the composite material mesh 200. Preferably, the rear end plate 302 is composed of one or more composite material panels. Preferably, the front end face of the web 301 is connected to the composite material panel, and the geometry of the front end face is consistent with the geometry of the surface of the composite material mesh. This avoids any residual elastic deformation and residual stress, ensuring that the geometry of the reflective surface of the fabricated reflector is consistent with the designed geometry.

[0072] Preferably, the rear end plate is also prepared using a sub-block layup method. Preferably, the distance between the T-shaped reinforcing rear end plate and the composite material mesh is as large as possible; a larger distance results in greater stiffness and better stability of the entire reflector. Preferably, the T-shaped reinforcing rear end plate is optional depending on design requirements. Preferably, the rear end plate can be composed of one or more continuous surfaces; more preferably, the rear end plate can be a curved surface, a plane, a continuous surface formed by multiple planes, or a combination of planes and curved surfaces. These surfaces can be closed or porous. Figure 4 As shown, the rear end plate can be a continuous surface formed by multiple planes and curved surfaces, with multiple triangular holes on the continuous surface.

[0073] Preferably, in this embodiment, the reflective panel 100, the composite material mesh 200, and the reinforcing structure 300 are all made of the same carbon fiber composite prepreg. Therefore, accuracy problems caused by mismatch in thermal expansion of the materials can be avoided.

[0074] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for manufacturing a reflector, characterized in that, Includes the following steps: The geometry of the working surface of the curing mold for the reflective panel is obtained by using an iterative accuracy compensation method. A metal layer is formed on the curing mold; A reflective panel is formed on the metal layer using a sub-block layup method; wherein the sub-block layup step includes: Based on the required geometry of the composite laminate, each layer of the composite laminate is divided into multiple sub-blocks; the prepreg is cut according to the geometry of the sub-blocks to obtain the sub-blocks; the sub-blocks are spliced ​​and laid up to obtain the required composite laminate. Composite meshes were prepared using a symmetrical balanced layup method; The composite material mesh is assembled onto the reflective panel; Assemble the reinforcing structure on the composite material mesh. The reflector is prepared in such a manner, wherein The reflective panel, the composite mesh, and the reinforcing structure are made of the same carbon fiber composite prepreg. The steps of the iterative accuracy compensation method include: Step 11: Based on the geometry of the target reflective panel, establish an initial finite element model of the curing mold and the reflective panel, wherein the reflective panel is placed in the curing mold. Step 12: Determine the temperature difference ΔT between the curing temperature of the reflector panel material and the assembly temperature of the reflector. Step 13: Cool the initial finite element model by ΔT to induce thermal deformation. Step 14: Extract the geometry and stress distribution of the cured reflective panel from the finite element model after thermal deformation. Step 15: Obtain the geometry of the cured reflective panel based on the extracted geometry and stress distribution of the cured reflective panel. Step 16: Compare the geometry of the cured reflective panel obtained in Step 15 with the geometry of the target reflective panel to obtain the geometric difference. Step 17: Based on the geometric difference, compensate the geometry of the curing mold to obtain the compensated geometry of the curing mold; Step 17 also includes, Set a threshold value, and compare the geometric difference value with the threshold value. When the geometric difference is less than or equal to the threshold A curing mold for the reflective panel is prepared according to the geometry of the compensated curing mold; When the geometric difference is greater than the threshold Based on the geometry of the compensated curing mold, a one-element finite element model of the curing mold and the reflective panel is established, wherein the reflective panel is placed in the curing mold. Repeat steps 12-17.

2. The preparation method according to claim 1, characterized in that, The reinforcement structure is a T-shaped structure. The T-shaped structure includes a web and a rear end plate connected to the web. The web is connected to the composite material mesh. The rear panel is composed of one or more composite material panels.

3. The preparation method according to claim 2, characterized in that, The front end face of the web is connected to the composite material mesh, and the geometry of the front end face is consistent with the geometry of the surface of the composite material mesh. The rear end plate of the reinforced structure is prepared by a sub-block layup method.

4. The preparation method according to claim 1, characterized in that, The step of assembling the composite material mesh onto the reflective panel includes: The composite material mesh is laid on the reflective panel using a symmetrical balanced layup method. The reflective panel and the composite material mesh are co-cured. The composite material mesh is assembled onto the reflective panel through co-curing.

5. The preparation method according to claim 1, characterized in that, The step of assembling the composite material mesh onto the reflective panel includes... The reflective panel is fabricated by layup of sub-blocks and then cured and shaped. A composite material mesh was prepared using a symmetrical balanced layup method and then cured and molded. The composite material is bonded to the reflective panel by adhesive bonding.

6. A reflector manufactured by the method according to any one of claims 1 to 5, comprising a reflective panel, a metal layer fixed to the reflective surface of the reflective panel, and a composite material mesh fixed to a surface of the reflective panel opposite to the reflective surface, characterized in that, It also includes a reinforcing structure connected to the composite material mesh. The reflective panel is composed of multiple sub-blocks. The composite material network consists of multiple symmetrically balanced layers. The reflective panel, the composite mesh, and the reinforcing structure are all made from the same carbon fiber composite prepreg.

7. The reflector as claimed in claim 6, characterized in that, The reinforcement structure is a T-shaped structure. The T-shaped structure includes a web and a rear end plate connected to the web. The web is connected to the composite material mesh. The rear panel consists of one or more composite material panels.

8. The reflector as claimed in claim 7, characterized in that, The front end face of the web is connected to the composite material mesh, and the geometry of the front end face is consistent with the geometry of the surface of the composite material mesh.

9. The reflector as claimed in claim 6, characterized in that, The reflective panel comprises multiple quasi-isotropic plies, each ply consisting of multiple sub-blocks, and the boundaries between the sub-blocks of adjacent layers do not coincide.

Images