Connecting method of fiber composite parts and application of connecting method

Abstract

The invention discloses a fiber composite part connecting method and application thereof, and belongs to the field of material connection. In order to solve the problems that an existing radome is poor in connection strength and affects the working performance, the connection method of the fiber composite part is provided and comprises the steps that the fiber composite part is prepared through prepreg, the laying layer number of the prepreg is # imgabs0, and h is the thickness of the fiber composite part; and an adhesive is smeared on the area, needing to be connected, in the fiber composite part, and adhesive connection between the fiber composite part and the object to be connected is completed through the adhesive. Connection is conducted in an adhesive mode, the sealing performance is good, and the bonding strength is high; compared with welding, mechanical connection and other modes, the structure of the fiber composite part cannot be damaged, meanwhile, complex machines or expensive resources do not need to be used, and the overall manufacturing cost is low; the damage to the fiber composite part is reduced while stable connection and stable strength of the fiber composite part and the to-be-connected object are ensured, so that the fiber composite part can meet the use requirements in special fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of material connection, and more specifically, relates to a connection method of fiber composite parts and application thereof. Background Art

[0002] The existence of the radome prolongs the service life of the antenna, simplifies the structure of the antenna, and reduces the weight of the structure. As an important component of the radar system, the performance of the radome directly affects the function of the radar system. It can be said that the radome is as important as the antenna. It is required that the radome has the least impact on the electromagnetic radiation characteristics of the antenna and meet the requirements of tactical and technical indicators. The radome technology integrates the knowledge of materials, processes, mechanics, electromagnetics, aerodynamics and structural mechanics, and is difficult to design and manufacture. Since the radome works in a complex and special environment, the requirements for materials are very strict, and it mainly uses glass fiber composite materials. The radome is usually connected to the equipment with bolts. However, the reliability of the bolt connection is not indestructible, and there are two major "vulnerabilities" hidden in it: fastening failure and tightening abnormality. Fastening failure: As the name suggests, the bolt or the connector itself cannot maintain its predetermined fastening state when subjected to external loads due to defects in materials, design or manufacturing, thereby losing its due connection function. This failure is often accompanied by bolt breakage, thread damage, loosening of connectors, etc., and in severe cases may even cause equipment damage or safety accidents. Abnormal tightening: Compared with fastening failure, abnormal tightening is often more hidden. It is usually related to operational errors, equipment failures or environmental interference during the tightening process. Although it will not directly cause the bolt material to reach its physical limit or fail, it will seriously affect the accuracy and consistency of the tightening process, and thus indirectly affect the quality and reliability of the bolt connection. At the same time, bolts are generally made of metal materials, which in some cases will affect the transmission performance of electromagnetic waves, so it is necessary to find a way to replace bolts to connect the antenna cover.

[0003] For example, Chinese patent application number CN202410694551.6, published on August 27, 2012, discloses a bonding and clamping device for assembling a hemispherical wave-transparent antenna cover, the device includes a base, a cover body positioning device is arranged in the middle of the base; the cover body positioning device is used to accommodate and position the antenna cover body, the antenna cover body is provided with an antenna cover aerogel, and the antenna cover body is provided with an antenna cover connecting ring; a connecting ring positioning device is arranged above the cover body positioning device, and the connecting ring positioning device is used to position the antenna cover connecting ring; the base, the cover body positioning device and the connecting ring positioning device are positioned by positioning pins; a central support frame is arranged above the base, and an aerogel fixing assembly is arranged in the middle of the central support frame, and the aerogel fixing assembly extends downward to fit and abut against the antenna cover aerogel; and a number of pressure rod assemblies are also arranged on the central support frame. The shortcomings of this patent are: complex structure and low efficiency.

[0004] Another example is Chinese patent application number CN202110294009.8, published on July 2, 2021. The patent discloses a bonding process for a ceramic wave-transmitting material antenna cover connecting ring. The adhesive is composed of a curing agent and a dispersant. The bonding process includes the following steps: (1) preparation before bonding; (2) bonding of the antenna cover and the connecting ring; (3) curing after bonding. The disadvantage of this patent is that the bonding quality is poor and cannot meet the use requirements in specific situations. Summary of the invention

[0005] 1. Problems to be solved

[0006] In view of the problem that the existing antenna cover has poor connection strength and affects working performance, the present invention provides a fiber composite connection method and its application. The present invention connects by gluing, which has good sealing and high bonding strength. Compared with welding, mechanical connection and other methods, it will not damage the structure of the fiber composite itself, and does not require the use of complex machinery or expensive resources, and the overall production cost is low. While ensuring that the fiber composite is firmly connected to the object to be connected and the strength is stable, it reduces damage to the fiber composite itself, so that it can meet the use requirements in special fields.

[0007] 2. Technical solution

[0008] To solve the above problems, the present invention adopts the following technical solutions.

[0009] A method for connecting fiber composite parts, comprising the following steps:

[0010] S1: Preparation of fiber composite parts using prepreg, number of prepreg layers Where h is the thickness of the fiber composite;

[0011] S2: The area of ​​the fiber composite component to be connected is coated with adhesive, and the fiber composite component and the object to be connected are bonded together by the adhesive.

[0012] By adopting the above technical solution, the fiber composite parts are connected by gluing. The connection parts made by this connection method have good sealing performance and high bonding strength. Compared with welding and mechanical connection methods, it will not damage the structure of the fiber composite part itself, and can also improve the defect of stress concentration between the fiber composite part and the object to be connected, thereby extending the service life of the connection structure. In particular, when the fiber composite parts connected by gluing are used in high-precision fields such as aerospace, the gluing method will not affect the overall wave transmission performance because there is no conductor such as metal in the structure.

[0013] At the same time, before gluing, the number of prepreg plies is determined to prepare the fiber composite. By accurately controlling the number of prepreg plies, it is possible to ensure that the fiber composite reaches the required thickness, thereby ensuring the structural strength of the fiber composite itself; and by reasonably designing the number of plies, the performance of the fiber composite can be optimized to meet the needs of use in specific fields; at the same time, it is possible to avoid uneven surfaces or defects on the fiber composite caused by unreasonable design of the number of plies, thereby affecting the subsequent gluing effect, so that a stronger bond is formed between the fiber composite and the adhesive, thereby improving the overall bonding effect.

[0014] The entire connection method is simple to operate, does not require the use of complex machinery or expensive resources, and has a low overall production cost. It ensures that the fiber composite is firmly connected to the object to be connected and has stable strength while reducing damage to the fiber composite itself, so that it can meet the use requirements in special fields.

[0015] Furthermore, the step S2 comprises:

[0016] S21: performing surface pretreatment on the area to be connected in the fiber composite, wherein the surface pretreatment includes physical surface treatment and chemical surface treatment;

[0017] S22: Apply adhesive to the area to be connected in the fiber composite part;

[0018] S23: applying adhesive to the areas of the objects to be connected to complete the adhesive connection between the fiber composite component and the objects to be connected, thereby forming a connection prefabricated component;

[0019] S24: placing the connection prefabricated component in a constant temperature and pressure environment to solidify the adhesive in the connection prefabricated component, thereby achieving adhesive connection between the fiber composite component and the object to be connected.

[0020] By adopting the above technical scheme, the surface of specific areas of the fiber composite is pretreated before gluing to facilitate better subsequent gluing; physical surface treatment can effectively remove surface impurities of the fiber composite and increase the roughness of the surface of the fiber composite, thereby improving the mechanical bite force between the adhesive and the fiber composite and enhancing the connection strength; chemical surface treatment can change the surface polarity to make it more compatible with the polarity of the adhesive, thereby improving the adhesion with the adhesive; the use of a combination of the two methods for pretreatment can significantly improve the adhesion and connection strength between the fiber composite and the adhesive, and can be applicable to a wider range of material applications.

[0021] Furthermore, the physical surface treatment in step S21 includes sandpaper polishing or sandblasting, and after the physical surface treatment, the surface roughness of the area where the fiber composite needs to be connected is 1.6 to 4.8; the chemical surface treatment includes one of plasma treatment, acid washing or alkaline washing.

[0022] By adopting the above technical solution, the surface roughness of the fiber composite is maintained within a certain range, so that it can be better combined with the adhesive, thereby improving the bonding strength and stability; at the same time, the surface roughness within this range can help the adhesive to form a uniform distribution on the surface of the fiber composite, avoiding local lack of glue or excessive thickness of the glue layer, thereby ensuring the uniformity and consistency of the bonding, and ensuring the bonding strength and stability.

[0023] Furthermore, when the chemical surface treatment is performed by plasma treatment, the area to be connected in the fiber composite is 10 to 30 mm away from the plasma nozzle, and the plasma treatment time is 90 to 150 seconds.

[0024] By adopting the above technical scheme, the distance between the fiber composite and the plasma nozzle is determined so that the active particles of the plasma can fully act on the surface of the fiber composite, thereby having a better modification effect on the surface of the fiber composite and ensuring that the surface of the fiber composite will not be damaged; the plasma treatment time is determined to avoid wasting resources due to too long time and failing to fully modify the surface of the fiber composite due to too short time.

[0025] Furthermore, in step S1, the prepreg is laid in one of 0°, ±45°, 0° / 90°, and quasi-isotropic. With the above technical solution, there are many choices of laying methods, making the preparation of fiber composite parts simpler and easier to operate.

[0026] Furthermore, in step S22, the adhesive forms an adhesive layer in the fiber composite component, and the thickness of the adhesive layer is 0.1-4 mm.

[0027] By adopting the above technical solution, the thickness of the adhesive layer is strictly controlled to avoid bubbles and gaps easily generated in an overly thick adhesive layer, which leads to poor connection quality and easy detachment between the connecting parts; an overly thin adhesive layer has poor connection stability and connection strength.

[0028] An application of the above-mentioned fiber composite connection method is to apply the fiber composite connection to the antenna cover connection, that is, the fiber composite material is the antenna cover.

[0029] By adopting the above technical solution, the antenna cover is mainly made of glass fiber composite materials. When connecting the antenna cover to the object to be connected, due to its complex and special environment, the use of gluing can not only ensure the stability of the connection, but also will not affect its work, that is, there will be no mechanical connection of metal parts that affects the transmission performance of electromagnetic waves.

[0030] Furthermore, the prepreg of the radome in step S1 includes fibers and a resin matrix; the fibers are one of glass fibers, polyester fibers, and polyimide fibers; and the resin matrix is ​​a thermosetting resin or a thermoplastic resin.

[0031] Furthermore, in step S1, the prepreg is used to prepare the radome by hand lay-up or resin transfer molding. If the radome is produced on a small scale or at low cost, hand lay-up can be used; if quality and efficiency are required, resin transfer molding can be used; different methods are selected according to different situations to improve practicality.

[0032] Furthermore, the present application also includes an antenna assembly, which includes an antenna component, a radome and a connecting plate, the antenna component is arranged on the connecting plate, the radome is arranged on the antenna component to seal the antenna component, and the connection between the radome and the connecting plate adopts the connection method of the fiber composite described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the process of the present invention;

[0034] Figure 2 is a schematic diagram of the structure of an antenna assembly;

[0035] In the figure: 1. Radome; 2. Connecting plate; 3. Glue layer. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific embodiments and drawings.

[0037] A method for connecting fiber composite parts, comprising the following steps:

[0038] S1: Preparation of fiber composite parts using prepreg, number of prepreg layers Where h is the thickness of the fiber composite;

[0039] S2: The area to be connected in the fiber composite is coated with adhesive, and the fiber composite and the object to be connected are bonded together by the adhesive.

[0040] It should be noted here that fiber composites are widely used in many high-end fields, such as aerospace, national defense, biomedicine, and electronics, due to their excellent properties such as light weight, high strength and high modulus, fatigue resistance, corrosion resistance, strong designability, and easy processing and molding. When used in these high-end fields, fiber composites will inevitably be connected to other objects, especially in the aerospace field. The existing fiber composite connection method usually adopts a mechanical connection method. This method will cause damage to the fiber composite itself, such as fiber breakage and matrix cracking, thereby reducing the strength and rigidity of the connection part; and mechanical connection usually introduces metal fasteners, which brings additional electromagnetic interference or shielding effect, thereby affecting its wave transmission. There are also a small number of fiber composites that are connected by gluing, but only by controlling the gluing parameters such as time and temperature to achieve the effect of gluing stability, but the effect is often unsatisfactory.

[0041] Therefore, a major innovation of the present application is to achieve the connection of fiber composites by gluing. This connection method has good sealing and high bonding strength. Compared with welding and mechanical connection methods, it will not damage the structure of the fiber composite itself, and can also improve the defect of stress concentration between the fiber composite and the object to be connected. Especially when the fiber composite is used in high-tech fields such as aerospace, the gluing method will not affect the overall wave transmission performance. Another major innovation is that by determining the number of prepreg plies according to the thickness of the fiber composite before gluing, by accurately controlling the number of prepreg plies, it is possible to ensure the overall thickness and performance of the fiber composite, while avoiding material waste or insufficient performance due to insufficient or excessive number of plies, thereby improving material utilization and saving resources and costs; more importantly, after determining the number of plies, the gluing step of the process is more controllable, and the time, temperature and other parameters can be more accurately controlled according to the number of plies, thereby improving the stability of the gluing effect and the reliability of the connection strength; and by accurately controlling the number of plies, it is possible to avoid the uneven surface of the fiber composite or the presence of bubbles, gaps and other defects caused by unreasonable design of the number of plies, which affects the subsequent gluing effect, so that a stronger bond is formed between the fiber composite and the adhesive, thereby improving the overall bonding effect.

[0042] The entire connection method of the present application is simple to operate, does not require the use of complex machinery or expensive resources, and has a low overall production cost. While ensuring a firm connection and stable strength between the fiber composite and the object to be connected, it reduces damage to the fiber composite itself, allowing it to meet the use requirements in special fields.

[0043] In a specific embodiment, the step S2 includes:

[0044] S21: performing surface pretreatment on the area to be connected in the fiber composite, wherein the surface pretreatment includes physical surface treatment and chemical surface treatment;

[0045] S22: Apply adhesive to the area to be connected in the fiber composite part;

[0046] S23: applying adhesive to the areas of the objects to be connected to complete the adhesive connection between the fiber composite component and the objects to be connected, thereby forming a connection prefabricated component;

[0047] S24: placing the connection prefabricated component in a constant temperature and pressure environment to solidify the adhesive in the connection prefabricated component, thereby achieving adhesive connection between the fiber composite component and the object to be connected.

[0048] Specifically, in this embodiment, before the fiber composites are connected, the surface pretreatment operation is also performed on the areas where the fiber composites need to be connected. The surface pretreatment is to make the subsequent gluing process smoother and more stable. In order to further ensure the effect of the surface pretreatment, this embodiment uses a combination of physical surface treatment and chemical surface treatment. Physical surface treatment can quickly and effectively remove surface impurities of the fiber composites, and increase the roughness of the surface of the fiber composites, thereby increasing the mechanical bite force between the adhesive and the fiber composites, and thus enhancing the connection strength; chemical surface treatment changes the surface polarity of the areas where the fiber composites need to be connected, so that they are more compatible with the polarity of the adhesive, thereby improving the adhesion between the adhesive and the fiber composites, and thus enhancing the connection strength.

[0049] In a specific embodiment, the physical surface treatment in step S21 includes sandpaper polishing or sandblasting, and the surface roughness Ra of the area where the fiber composite needs to be connected after the physical surface treatment is 1.6 to 4.8; the chemical surface treatment includes one of plasma treatment, acid washing or alkaline washing.

[0050] Both sandpaper polishing and sandblasting are relatively simple to use, and do not require the use of complex mechanical equipment for physical surface treatment. They are easy for workers to use and have high work efficiency. At the same time, the surface roughness of the area where the fiber composite needs to be connected is limited. The surface roughness can increase the contact area between the adhesive and the fiber composite. Limiting it not only ensures full bonding with the adhesive, but also avoids poor wetting and bonding defects caused by excessive roughness, thereby ensuring subsequent bonding strength. Chemical surface treatments such as plasma treatment, acid pickling or alkaline washing are simple to operate, ensuring the treatment effect while improving the treatment efficiency.

[0051] In a specific embodiment, when the chemical surface treatment is performed by plasma treatment, the area to be connected in the fiber composite is 10 to 30 mm away from the plasma nozzle, and the plasma treatment time is 90 to 150 seconds.

[0052] Plasma surface treatment is to change the chemical properties of the material surface by using the chemical reaction produced by plasma technology on the material surface. It has high processing efficiency and is easy to operate. Therefore, plasma surface treatment is used to modify the surface of the fiber composite. In this embodiment, the distance between the area to be connected in the fiber composite and the plasma nozzle, as well as the processing time, are strictly controlled. The distance is determined so that the active particles of the plasma can fully act on the surface of the fiber composite, thereby having a good modification effect on the surface of the fiber composite and ensuring that the surface of the fiber composite will not be damaged; the time is determined to avoid wasting resources due to too long a time, and the surface of the fiber composite cannot be fully modified due to too short a time.

[0053] In a specific embodiment, in step S1, the prepreg is laid in one of 0°, ±45°, 0° / 90°, and quasi-isotropic. Multiple laying methods are available, making the preparation of fiber composites simpler and easier to operate. The laying method can be completely hand-laid glass fiber cloth, or a honeycomb layer or foam sandwich panel can be set in the middle, etc., which can be selected according to the specific situation.

[0054] In a specific embodiment, in step S22, the adhesive forms an adhesive layer in the fiber composite component, and the thickness of the adhesive layer is 0.1-4 mm.

[0055] Specifically, the thickness of the adhesive layer is strictly controlled to avoid excessively thick adhesive layers that easily generate bubbles and voids, resulting in poor connection quality and easy detachment between the connecting parts; excessively thin adhesive layers have poor connection stability and connection strength.

[0056] The present application also provides an application of the method for connecting the fiber composites described in any one of the above items, wherein the connection of the fiber composites is applied to the connection of antenna covers, that is, the fiber composite material is an antenna cover.

[0057] It is explained here that the radome is used to protect the antenna on the aircraft. It needs to withstand extreme environments such as high temperature, high-speed airflow, sand, etc., so the material of the radome is usually glass fiber composite material. In the connection of the radome, bolts are usually used to connect with the equipment. The metal material of the bolts will affect the permeability of electromagnetic waves. Therefore, this application uses gluing to connect the radome to the object to be connected. It has high bonding strength, good sealing, uniform stress distribution, good wave permeability and can be mass-produced. Its bonding strength can reach more than 33MPa, and there is no damage to the radome itself, thereby ensuring that the strength and work of the radome itself are not affected.

[0058] In a specific embodiment, the prepreg of the antenna cover in step S1 includes fibers and a resin matrix; the fibers are one of glass fibers, polyester fibers, and polyimide fibers; the resin matrix is ​​a thermosetting resin or a thermoplastic resin, and the thermosetting resin can be one of epoxy resin (EP), phenolic resin, unsaturated polyester, and bismaleimide; the thermoplastic resin is one of polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyphenylene sulfide (PPS), polyetherimide (PEI), and polyphenylene sulfone (PPSU).

[0059] In a specific embodiment, the prepreg in step S1 is used to prepare the radome by hand lay-up or resin transfer molding. If the radome is produced on a small scale or at low cost, hand lay-up can be used; if quality and efficiency are required, resin transfer molding (RTM) can be selected; different methods are selected according to different situations to improve practicality.

[0060] like Figure 2 As shown, the present application also provides an antenna assembly, which includes an antenna component, a radome and a connecting plate, on which the antenna component is arranged, and the radome is provided on the antenna component to seal the antenna component, and the connection between the radome and the connecting plate adopts the connection method of the fiber composite described above.

[0061] In order to further understand the technical solution and application field of this application, the following examples are given:

[0062] Example 1

[0063] This embodiment is a method for connecting glass fiber reinforced PEEK resin-based composite parts, which includes the following steps:

[0064] S1: First, according to certain size and thickness requirements of glass fiber reinforced PEEK resin-based composite parts, cut carbon fiber reinforced PEEK resin-based fiber reinforced composite material prepreg for curing, or adopt hand lay-up or RTM molding to prepare fiber reinforced composite parts; cut the fiber reinforced composite parts according to the size specifications of the connecting parts to obtain the fiber reinforced composite material substrate;

[0065] S21: Sandblast the part of the fiber reinforced composite material substrate that needs to be bonded. Use a sandblasting machine for sandblasting. The sandblasting pressure is 2-5MPa, the sandblasting distance is 100-300mm, and the surface roughness Ra after sandblasting is in the range of 1.6-4.8. Plasma treatment is performed on the area after sandblasting. During plasma treatment, the distance between the composite plate to be bonded and the plasma nozzle is 10-30mm, and the treatment time is 90-150s;

[0066] S22: Apply adhesive to the area where the fiber reinforced composite material substrate needs to be bonded, and then cover another fiber reinforced composite material substrate on the adhesive to form a connected prefabricated part;

[0067] S23: Place the connector preform into a pressurized heating device, and then use the pressurized heating device to pressurize and heat according to the curing process of the adhesive to cure the adhesive and finally obtain a connector of a fiber-reinforced composite material and a fiber-reinforced composite material. The final connector is tested according to GB / T 33334-2016 standard, and its bonding strength can reach more than 33MPa.

[0068] Example 2

[0069] This embodiment is a method for connecting glass fiber reinforced PAEK resin-based composite parts to glass fiber reinforced PAEK resin-based composite parts, which includes the following steps:

[0070] S1: First, according to certain size and thickness requirements of glass fiber reinforced PAEK resin-based composite parts, cut carbon fiber reinforced PAEK resin-based fiber reinforced composite material prepreg for curing, or adopt hand lay-up or RTM molding to prepare fiber reinforced composite parts; cut the fiber reinforced composite parts according to the size specifications of the connecting parts to obtain the fiber reinforced composite material substrate;

[0071] S21: The part of the fiber reinforced composite material substrate to be bonded is polished with sandpaper, the mesh number of the sandpaper is controlled between 80-400 mesh, and the surface roughness Ra after polishing is in the range of 1.6-4.8; then plasma treatment is performed, during which the distance between the composite plate to be bonded and the plasma nozzle is 10-30mm, and the treatment time is 90-150s;

[0072] S22: Apply adhesive to the area where the fiber reinforced composite material substrate needs to be bonded, and then cover another fiber reinforced composite material substrate on the adhesive to form a connected prefabricated part;

[0073] S23: Place the connector preform into a pressurized heating device, and then use the pressurized heating device to pressurize and heat according to the curing process of the adhesive to cure the adhesive and finally obtain a connector of a fiber-reinforced composite material and a fiber-reinforced composite material. The final connector is tested according to GB / T 33334-2016 standard, and its bonding strength can reach more than 33MPa.

[0074] Example 3

[0075] This embodiment is a method for connecting glass fiber reinforced epoxy resin-based composite parts to glass fiber reinforced epoxy resin-based composite parts, which includes the following steps:

[0076] S1: First, according to certain size and thickness requirements of glass fiber reinforced epoxy resin-based composite parts, cut carbon fiber reinforced epoxy resin-based fiber reinforced composite material prepregs for curing, or adopt hand lay-up or RTM molding to prepare fiber reinforced composite parts; cut the fiber reinforced composite parts according to the size specifications of the connecting parts to obtain fiber reinforced composite material substrates;

[0077] S21: Cut off the poor quality parts around the fiber reinforced composite substrate, and use a sandblasting machine to sandblast the side that needs to be bonded. The sandblasting pressure is 2-5MPa, the sandblasting distance is 100-300mm, and the surface roughness Ra after sandblasting is in the range of 1.6-4.8. Plasma treatment is performed on the area after sandblasting. During plasma treatment, the distance between the composite plate to be bonded and the plasma nozzle is 10-30mm, and the treatment time is 90-150s;

[0078] S22: Apply adhesive to the area where the fiber reinforced composite material substrate needs to be bonded, and then cover another fiber reinforced composite material substrate on the adhesive to form a connected prefabricated part;

[0079] S23: Place the connector preform into a pressurized heating device, and then use the pressurized heating device to pressurize and heat according to the curing process of the adhesive to cure the adhesive and finally obtain a connector of a fiber-reinforced composite material and a fiber-reinforced composite material. The final connector is tested according to GB / T 33334-2016 standard, and its bonding strength can reach more than 33MPa.

[0080] Example 4

[0081] This embodiment is a method for connecting a glass fiber reinforced unsaturated polyester resin-based composite member to another glass fiber reinforced unsaturated polyester resin-based composite member, which comprises the following steps:

[0082] S1: First, according to certain size and thickness requirements of glass fiber reinforced unsaturated polyester resin-based composite parts, cut glass fiber reinforced unsaturated polyester resin-based fiber reinforced composite material prepreg for curing, or adopt hand lay-up or RTM molding to prepare fiber reinforced composite parts; cut the fiber reinforced composite parts according to the size specifications of the connecting parts to obtain the fiber reinforced composite material substrate;

[0083] S21: Cut off the poor quality parts around the fiber reinforced composite substrate, and use a sandblasting machine to sandblast the side that needs to be bonded. The sandblasting pressure is 2-5MPa, the sandblasting distance is 100-300mm, and the surface roughness Ra after sandblasting is in the range of 1.6-4.8. Plasma treatment is performed on the area after sandblasting. During plasma treatment, the distance between the composite plate to be bonded and the plasma nozzle is 10-30mm, and the treatment time is 90-150s;

[0084] S22: Apply adhesive to the area where the fiber reinforced composite material substrate needs to be bonded, and then cover another fiber reinforced composite material substrate on the adhesive to form a connected prefabricated part;

[0085] S23: Place the connector preform into a pressurized heating device, and then use the pressurized heating device to pressurize and heat according to the curing process of the adhesive to cure the adhesive and finally obtain a connector of a fiber-reinforced composite material and a fiber-reinforced composite material. The final connector is tested according to GB / T 33334-2016 standard, and its bonding strength can reach more than 33MPa.

[0086] The bonding strength of the fiber composites after pretreatment in the four groups of embodiments is tested and shown in Table 1 below. After the fiber composites are treated with plasma for more than 90 seconds, the bonding strength can be basically stabilized at about 33±2 MPa.

[0087] Table 1 Bond strength of fiber composites at different plasma treatment times

[0088]

[0089] In order to further demonstrate the advantages of accurately controlling the number of prepreg layers by determining the number of prepreg layers according to the thickness of the fiber composite before gluing, the applicant has conducted the following experiments:

[0090] Different methods are used to connect the fiber composites (composite panels with an area of ​​260*260). The first method is to use the solution described in the present application, that is, to determine the number of prepreg layers according to the thickness of the fiber composite, and then complete the adhesive connection; the second method is to directly prepare the fiber composite by hand lay-up, and then complete the adhesive connection; the third method is to directly prepare the fiber composite by vacuum infusion, and then complete the adhesive connection; the material consumption of these three methods is compared, and the material consumption here mainly refers to the total weight of the fiber and the resin, in g, as shown in Table 2:

[0091]

[0092] It can be seen that by determining the number of prepreg layers according to the thickness of the fiber composite before gluing, material waste or insufficient performance due to insufficient or excessive number of layers can be avoided, material utilization can be improved, and resources and costs can be saved.

[0093] At the same time, different methods are used to connect the fiber composite parts. The first method is to use the solution described in the present application, that is, to determine the number of prepreg layers according to the thickness of the fiber composite part, and then complete the adhesive connection; the second method is to directly prepare the fiber composite part by hand lay-up, and then complete the adhesive connection; the third method is to directly prepare the fiber composite part by vacuum infusion, and then complete the adhesive connection; finally, the shear strength of the connection of these three methods is compared, as shown in Table 3:

[0094]

[0095] It can be seen that by determining the number of prepreg layers according to the thickness of the fiber composite before gluing, the overall thickness and performance of the fiber composite can be guaranteed by accurately controlling the number of prepreg layers.

[0096] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A method for connecting fiber composite parts, characterized in that: The following steps are involved: S1: Preparation of fiber composite parts using prepreg, number of prepreg layers Where h is the thickness of the fiber composite; S2: The area of ​​the fiber composite component to be connected is coated with adhesive, and the fiber composite component and the object to be connected are bonded together by the adhesive.

2. A method for connecting fiber composite parts according to claim 1, characterized in that: The step S2 comprises: S21: performing surface pretreatment on the area to be connected in the fiber composite, wherein the surface pretreatment includes physical surface treatment and chemical surface treatment; S22: Apply adhesive to the area to be connected in the fiber composite part; S23: applying adhesive to the areas of the objects to be connected to complete the adhesive connection between the fiber composite component and the objects to be connected, thereby forming a connection prefabricated component; S24: placing the connection prefabricated component in a constant temperature and pressure environment to solidify the adhesive in the connection prefabricated component, thereby achieving adhesive connection between the fiber composite component and the object to be connected.

3. A method for connecting fiber composite parts according to claim 2, characterized in that: The physical surface treatment in step S21 includes sandpaper polishing or sandblasting, and the surface roughness of the area where the fiber composite needs to be connected after the physical surface treatment is 1.6 to 4.8; the chemical surface treatment includes one of plasma treatment, acid washing or alkaline washing.

4. A method for connecting fiber composite parts according to claim 3, characterized in that: When the chemical surface treatment is performed by plasma treatment, the area to be connected in the fiber composite is 10 to 30 mm away from the plasma nozzle, and the plasma treatment time is 90 to 150 seconds.

5. The method for connecting fiber composite parts according to claim 1, characterized in that: In the step S1, the prepreg is laid in one of the following ways: 0°, ±45°, 0° / 90°, and quasi-isotropic.

6. A method for connecting fiber composite parts according to claim 2, characterized in that: In the step S22, the adhesive forms an adhesive layer in the fiber composite component, and the thickness of the adhesive layer is 0.1-4 mm.

7. An application of the fiber composite connection method according to any one of claims 1 to 6, characterized in that: The fiber composite connection is used for the connection of a radome, that is, the fiber composite is a radome.

8. Application of the fiber composite connection method according to claim 7, characterized in that: The prepreg of the radome in step S1 comprises fibers and a resin matrix; the fibers are one of glass fibers, polyester fibers, and polyimide fibers; and the resin matrix is ​​a thermosetting resin or a thermoplastic resin.

9. Application of the method for connecting fiber composite parts according to claim 7 or 8, characterized in that: In the step S1, the prepreg is used to prepare the antenna cover through a hand lay-up operation or a resin transfer molding operation.

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