A method for fabricating a resonant long airfoil wedge outer edge stealth structure component

Abstract

This invention discloses a method for manufacturing a resonant long-winged wedge stealth structure component, comprising the following steps: (1) designing a mold for forming the long-winged wedge stealth component; (2) preparing a stealth material blank for the long-winged wedge stealth component: weighing the stealth material, rolling it into a sheet, cutting and patching the stealth material film, and pre-forming the stealth material by stacking layers to obtain the stealth material blank for the long-winged wedge stealth component; (3) forming the long-winged wedge stealth component: placing the stealth material blank into a core mold, closing the mold, and vulcanizing to obtain the long-winged wedge stealth component; (4) bonding the long-winged wedge stealth component: bonding the long-winged wedge stealth component, vacuuming and compacting for curing, and performing post-processing to obtain the resonant long-winged wedge stealth structure component. This invention is reliable, highly repeatable, and allows for simultaneous forming and bonding, improving production efficiency and reducing the technological difficulty of forming the resonant long-winged wedge stealth structure component.

Description

Technical Field

[0001] This invention belongs to the technical field of manufacturing complex stealth structural components for aviation equipment, and relates to a method for manufacturing a resonant long airfoil wedge outer edge stealth structural component. Background Technology

[0002] The rapid development of radio technology and radar detection systems has made the target search and tracking capabilities of detection systems more precise. Multi-band joint detection technology has become an important means of monitoring military targets. The working principle of radar detection is to determine the existence and location of a target based on the energy scattered by the radar wave. To meet the needs of modern warfare, many pieces of equipment adopt stealth technology to prevent them from being detected and intercepted by enemy radar. The wing structure of a product is an important electromagnetic scattering component in the forward angular domain, and its radar echo mainly comes from the leading and trailing edges of the wing surface. The echo mechanism includes wing surface scattering, edge diffraction, and multiple scattering formed by coupling between the wing surface and the product body. Taking stealth measures on the wing structure can convert the electromagnetic energy of radar waves into thermal energy, mechanical energy, etc., and scatter them away, thereby reducing the interference of electromagnetic waves, attenuating the echo intensity, reducing the radar cross section, and improving the survivability of the equipment. In industrial production, stealth coatings are generally applied to structural components by spraying. Although spraying has the characteristics of multi-directionality, all-angle capability, and strong adaptability to the target shape, the spraying time is long and requires a high level of operator skill. For components with special structures, such as the outer edge of a wedge, spraying can result in two problems: firstly, the application rate of the absorbing coating is low, leading to significant waste; secondly, the thickness of the coating in certain areas cannot be guaranteed, increasing the difficulty of post-processing. Summary of the Invention

[0003] (I) Purpose of the Invention

[0004] The purpose of this invention is to provide a method for manufacturing a resonant long airfoil wedge outer edge stealth structure component, overcoming the limitations of spray-applied stealth materials and improving production efficiency; while simultaneously meeting the stealth function requirements of some structural components in aerospace equipment.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, this invention provides a method for manufacturing a resonant long airfoil wedge outer edge stealth structure component, comprising the following steps:

[0007] (1) Design of mold for forming long airfoil wedge outer edge stealth part: design of core mold for forming long airfoil wedge outer edge stealth part, design of upper mold and lower mold for forming long airfoil wedge outer edge stealth part, to obtain mold for forming long airfoil wedge outer edge stealth part.

[0008] (2) Stealth material blank for long airfoil wedge outer edge stealth component: weigh and prepare stealth material for long airfoil wedge outer edge stealth component, roll the stealth material into sheet, cut and patch stealth material film, and preform the stealth material by stacking layers to obtain stealth material blank for long airfoil wedge outer edge stealth component.

[0009] (3) Forming of the long airfoil wedge outer edge stealth component: The stealth material blank of the long airfoil wedge outer edge stealth component is placed into the core mold, and the mold is closed and vulcanized to obtain the long airfoil wedge outer edge stealth component.

[0010] (4) Bonding of the long airfoil wedge outer edge stealth component: The long airfoil wedge outer edge stealth component is bonded by adhesive bonding, vacuumed and compacted for curing, and then trimmed and treated to obtain the resonant long airfoil wedge outer edge stealth structure component.

[0011] Furthermore, in step (1), the core mold design for the long airfoil wedge outer edge stealth component is used to cover the stealth material stack blank on it. The outer surface of the core mold and the outer surface of the metal substrate airfoil wedge outer edge are designed in the same shape, which shapes the inner surface of the long airfoil wedge outer edge stealth component.

[0012] Furthermore, the upper and lower molds for forming the long airfoil wedge stealth component described in step (1) are designed to facilitate the forming of the long airfoil wedge stealth component. The inner surface of the mold is designed and processed according to the three-dimensional model of the long airfoil wedge stealth component, and the outer surface of the mold has a regular shape to facilitate uniform stress on the stealth material blank when the press is applied. In this experiment, a hydraulic press was used to press the mold to achieve a synchronous and rapid production rhythm. Of course, screw pressurization, autoclave, or other methods can also be used for pressurization, but are not limited to.

[0013] Positioning holes are opened at the end of the core mold and at the ends of the upper and lower molds. After the positioning holes are matched, positioning pins are used to fix the two together.

[0014] Furthermore, the stealth material blank for preparing the long airfoil wedge outer edge stealth component in step (2) is a radar wave absorbing layer.

[0015] More preferably, the radar wave absorbing layer is a two-layer or multi-layer microwave resonant structure absorbing layer. The radar wave absorbing layer selected in this experiment is a two-layer layer, wherein the microwaves absorbed by the first microwave resonant structure absorbing layer are in the C-band, and the microwaves absorbed by the second microwave resonant structure absorbing layer are in the Ku-band. The microwave resonant absorption efficiency of both layers is greater than or equal to 0.9.

[0016] More preferably, the stealth material is a microwave resonant structure absorption layer, which is made of raw rubber (uncured rubber) with added absorbents such as indium tin oxide, zinc aluminum oxide, graphite sheets or iron fibers to achieve efficient absorption of broadband radar waves. The stealth material combination used in this experiment has an electromagnetic wave reflectivity R ≤ -12dB in the frequency range between the C-band and the Ku-band. Production is not limited to two layers and this type of stealth material. Other stealth materials with higher electromagnetic reflectivity or better layer combinations can be selected according to actual needs.

[0017] Furthermore, in step (2), the cloaking material is rolled into sheets, and the block or clump of raw rubber cloaking material is rolled into sheets multiple times using a kneader.

[0018] More preferably, the kneading machine consists of a pair of smooth cylinders that cooperate and rotate with each other. The resulting squeezing force causes the stealth material to expel air bubbles from the film and knead it into a sheet shape.

[0019] Further, in step (2), the stealth material film is cut and patched using tools such as blades. The film is roughly cut according to the outline of the stealth part with the outer edge of the long wing-shaped wedge, and the missing material area is cut and patched.

[0020] Further, in step (2), the stealth material is pre-formed by stacking layers, with the first microwave resonant structure absorption layer on top and the second microwave resonant structure absorption layer on the bottom, and the two layers are stacked to obtain a stealth material blank for the long airfoil wedge outer edge stealth component.

[0021] Further, in step (3), the long airfoil wedge outer edge stealth material blank is placed into the core mold, and the long airfoil wedge outer edge stealth material blank is placed on the core mold according to the shape of the core mold.

[0022] Further, in step (3), the mold closing and vulcanization molding is carried out by placing the core mold of the stealth material blank with the long wing-shaped wedge outer edge in the lower mold through the positioning pin, applying pressure through the press, and closing and vulcanizing molding. The mold temperature is set to 130℃-135℃. When the temperature rises from 90℃ to within 110℃, the molding pressure is increased to 3MPa. At the same time, the pressure is kept so as not to drop before demolding. The temperature is kept at 130℃-135℃ for 4 hours, and then naturally cooled and demolded to obtain the long wing-shaped wedge outer edge stealth part.

[0023] Further, in step (4), the stealth component of the long airfoil wedge is bonded by adhesive bonding. The bonding surfaces of the stealth component of the long airfoil wedge and the outer edge of the metal substrate airfoil wedge are wiped clean, and a layer of commonly used epoxy adhesive is evenly applied. The adhesive used in this experiment is DG-3S (this adhesive is not limited to production; it can be selected as long as the bonding strength between the adhesive and the metal is better than the bonding strength between the stealth coating and the metal material. The application method is not limited to scraping; the adhesive viscosity can be adjusted for spraying or dotting). Using the wingtip as the reference point, the stealth component of the airfoil wedge is bonded and applied in a continuous manner according to the reserved groove on the outer edge of the metal substrate airfoil wedge.

[0024] Further, in step (4), vacuum compaction and curing are performed to ensure that the outer edge stealth component of the airfoil and the outer edge of the metal substrate are firmly and uniformly bonded without cracks or bulges, and that the adhesive layer is free of bubbles and defects after curing. After the outer edge stealth component of the airfoil and the metal substrate are bonded together, the whole is vacuumed and pressurized for curing.

[0025] More preferably, the vacuuming process should ensure that the pressure inside the vacuum bag is below -0.085 MPa and the vacuuming time is more than 4 hours.

[0026] Further, in step (4), the post-processing is performed to smoothly transition the bonding area of ​​the cured resonant long airfoil wedge outer edge stealth component. There should be no reverse flight step difference, and the flight step difference should be less than 0.2mm. The overall structure of the bonded long airfoil wedge outer edge stealth component meets the aerodynamic requirements and presents a streamlined shape, thus obtaining a resonant long airfoil wedge outer edge stealth structure component.

[0027] (III) Beneficial Effects

[0028] The method for fabricating the resonant long airfoil wedge outer edge stealth structure component provided by the above technical solution has the following beneficial effects:

[0029] (1) Innovatively, stealth materials with different properties are stacked and pre-formed, and then vulcanized and molded as a whole, making full use of the molding concept of composite materials and maximizing the resonance performance of stealth materials.

[0030] (2) Compared with the spraying preparation process, the molding and vulcanization of stealth materials is realized, with a short molding cycle and high dimensional accuracy.

[0031] (3) Using compression molding greatly saves the amount of raw materials compared to spray molding (spray molding has a long time span and low material loading).

[0032] (4) The use of adhesives makes the bonding strength between stealth materials and metal parts better than the bonding strength between stealth materials and metal parts in direct contact. At the same time, the modular and rolling production method ensures that each module does not affect the other.

[0033] (5) The molding method is reliable and highly repeatable. Molding and bonding can be carried out simultaneously, which improves production efficiency and reduces the process difficulty of molding the outer edge stealth structure component of the resonant long airfoil wedge. Attached Figure Description

[0034] Figure 1 A schematic diagram of the core mold structure for forming the outer edge of the long airfoil wedge stealth component.

[0035] Figure 2 A schematic diagram of the cross-sectional structure of the upper and lower molds for forming the stealth component with the outer edge of the long airfoil wedge.

[0036] Figure 3 This is a schematic diagram of the stealth material blank structure for the long airfoil-shaped wedge-shaped stealth component.

[0037] Figure 4 This is a schematic diagram of the stealth component on the outer edge of the long airfoil-shaped wedge.

[0038] Figure 5 This is a schematic diagram of the outer edge stealth structure component of the resonant long airfoil wedge.

[0039] The numbers in the diagram indicate: 1. Molding core mold; 2. Molding upper mold; 3. Molding lower mold; 4. Stealth material blank; 5. Long airfoil wedge outer edge stealth component; 6. Resonant long airfoil wedge outer edge stealth structure component. Detailed Implementation

[0040] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0041] The long-wing wedge-shaped stealth component is lightweight and low-cost. It can be adhesively bonded to the surface of a metal substrate's wedge-shaped outer edge without altering the airfoil's shape. This satisfies the equipment's stealth requirements under different frequency bands while maintaining its operational capabilities. Its radar absorption range covers the C-band to the Ku-band, and its electromagnetic reflectivity R ≤ -12dB.

[0042] The fabrication method of the resonant long airfoil wedge outer edge stealth structure component in this embodiment includes the following steps:

[0043] (1) Design of mold for forming stealth components with long airfoil wedge outer edge

[0044] like Figure 1 As shown, the function of the long airfoil wedge outer edge stealth component forming core mold 1 is to cover the long airfoil wedge outer edge stealth component stealth material blank 4 on the long airfoil wedge outer edge stealth component forming core mold. The outer surface of the long airfoil wedge outer edge stealth component forming core mold 1 and the outer surface of the metal substrate airfoil wedge outer edge are designed to shape the inner surface of the long airfoil wedge outer edge stealth component 5.

[0045] To facilitate the molding of the long airfoil-shaped wedge outer edge stealth component, an upper mold 2 and a lower mold 3 for molding the long airfoil-shaped wedge outer edge stealth component are designed, such as... Figure 2 As shown, the inner surface of the mold is designed and processed according to the three-dimensional model of the long airfoil wedge stealth component. The outer surface of the mold has a regular shape, which facilitates uniform stress on the stealth material blank 4 of the long airfoil wedge stealth component when the press is applied. In this experiment, a hydraulic press is used to pressurize the mold to synchronize the rapid production rhythm. Pressurization by screws, autoclaves or other methods can also be used, but are not limited to.

[0046] The mold for forming a long-winged wedge-shaped stealth component consists of a core mold 1, an upper mold 2, and a lower mold 3. The core mold 1 and the lower mold 3 have matching positioning pins to facilitate the insertion of the core mold 1. There are mold-closing guide pillars and guide pillar holes between the upper mold 2 and the lower mold 3 to facilitate mold positioning during mold closing. There are pressure blocks between the mold-closing seams of the upper mold 2 and the lower mold 3 to facilitate observation of whether the mold is properly closed and to prevent overpressure damage to the mold.

[0047] (2) Stealth material blank for long airfoil wedge outer edge stealth component

[0048] The stealth material blank 4, used to prepare the long-winged wedge-shaped stealth component, serves as the radar wave absorbing layer. This radar wave absorbing layer consists of two or more microwave resonant structure absorbing layers. The layer used in this experiment is two-layered, with the first layer absorbing microwave frequencies between the C and Ku bands, and the second layer absorbing microwave frequencies between the Ku bands. Both layers have a microwave resonant absorption efficiency greater than or equal to 0.9. The stealth material is a microwave resonant structure absorbing layer made of raw rubber (uncured rubber) with added absorbents such as indium tin oxide, zinc aluminum oxide, graphite sheets, or iron fibers to achieve efficient absorption of broadband radar waves. The stealth material used in this experiment has an electromagnetic wave reflectivity R ≤ -12dB within the Ku band frequency range. However, production is not limited to two layers or this type of stealth material; other stealth materials with higher electromagnetic reflectivity or better layer combinations can be selected according to actual needs. The block or lumpy stealth material is repeatedly kneaded into sheets using a kneader. Using blades and other tools, roughly cut the sheet material according to the unfolded shape of the long wing-shaped wedge stealth component, and trim to fill in any missing material areas. For example... Figure 3 As shown, the first microwave resonant structure absorption layer is placed on top, and the second microwave resonant structure absorption layer is placed on the bottom. The two layers are stacked to obtain the stealth material blank 4 of the long airfoil wedge outer edge stealth component.

[0049] (3) Forming of the long airfoil wedge outer edge stealth component

[0050] The stealth material blank 4 of the long-winged wedge stealth component is placed in the long-winged wedge stealth component molding core mold 1. The core mold with the long-winged wedge stealth material blank 4 is placed in the long-winged wedge stealth component molding lower mold 3 through the positioning pin. Pressure is applied by a press, and the mold is closed for vulcanization molding. The mold temperature is set at 130℃-135℃. When the temperature rises from 90℃ to 110℃, the molding pressure is gradually increased to 3MPa. The pressure is maintained before demolding. The temperature is held at 130℃-135℃ for 4 hours, and then naturally cooled to below 60℃ before demolding to obtain the desired result. Figure 4 5. Long wing-shaped wedge-shaped stealth component on the outer edge.

[0051] (4) Bonding of the long airfoil wedge outer edge stealth component

[0052] The stealth component 5 of the long airfoil wedge and the outer edge of the metal substrate airfoil wedge were wiped clean with alcohol. A layer of commonly used epoxy adhesive was then evenly applied. The adhesive layer can locally compensate for the defects of the bonding surface between the stealth component 5 of the airfoil wedge and the outer edge of the metal substrate airfoil wedge. The adhesive used in this experiment is DG-3S (this adhesive is not limited to production; it can be selected as long as the adhesion strength between the adhesive and the metal is better than the adhesion strength between the stealth coating and the metal material. The application method is not limited to scraping; the adhesive viscosity can be adjusted for spraying or dotting). Using the wingtip as a reference point, the stealth component of the airfoil wedge was sequentially bonded and applied according to the reserved groove on the outer edge of the metal substrate airfoil wedge.

[0053] To ensure a firm and uniform bond between the airfoil wedge outer edge stealth component 5 and the metal substrate, free from cracks and bulges, and to prevent air bubbles and defects within the cured adhesive layer, a vacuum pressure curing process is applied after the airfoil wedge outer edge stealth component 5 and the metal substrate are bonded. The vacuum bag pressure must be maintained below -0.085 MPa, and the vacuuming time must be at least 4 hours. The bonded area of ​​the cured airfoil wedge outer edge stealth component 5 should have a smooth transition, with no adverse heading step and a forward heading step less than 0.2 mm. The overall structure of the bonded airfoil wedge outer edge stealth component 5 should meet aerodynamic requirements and exhibit a streamlined shape, resulting in the desired effect. Figure 5 The above describes a resonant long airfoil wedge outer edge stealth structure component 6.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for manufacturing a resonant long airfoil wedge outer edge stealth structure component, characterized in that, Includes the following steps: (1) Design of mold for forming long airfoil wedge outer edge stealth part: design of core mold for forming long airfoil wedge outer edge stealth part, design of upper and lower mold for forming long airfoil wedge outer edge stealth part, to obtain mold for forming long airfoil wedge outer edge stealth part; (2) Stealth material blank for long airfoil wedge outer edge stealth component: weigh and prepare stealth material for long airfoil wedge outer edge stealth component, roll the stealth material into sheet, cut and patch stealth material film, and preform the stealth material by stacking to obtain stealth material blank for long airfoil wedge outer edge stealth component. (3) Forming of the long airfoil wedge outer edge stealth component: The stealth material blank of the long airfoil wedge outer edge stealth component is placed into the core mold, and the mold is closed and vulcanized to obtain the long airfoil wedge outer edge stealth component; (4) Bonding of the long airfoil wedge outer edge stealth component: The long airfoil wedge outer edge stealth component is bonded by adhesive bonding, vacuumed and compacted for curing, and then trimmed to obtain the resonant long airfoil wedge outer edge stealth structure component. In step (1), in the design of the core mold for forming the long airfoil wedge stealth component, the core mold is used to cover the stacked blank of stealth material. The outer surface of the core mold and the outer surface of the airfoil wedge of the metal substrate are designed in the same shape to shape the inner surface of the long airfoil wedge stealth component. In the design of the upper and lower molds for forming the long airfoil wedge stealth component, the inner surface of the upper and lower molds is designed and processed according to the shape of the three-dimensional model of the long airfoil wedge stealth component. The outer surface of the mold is a regular shape. The end of the core mold and the ends of the upper and lower molds are all provided with positioning holes. After the positioning holes are matched, positioning pins are used to fix the two. In step (2), the stealth material blank of the long airfoil wedge outer edge stealth component is a radar wave absorbing layer; the radar wave absorbing layer consists of two layers, in which the microwaves absorbed by the first microwave resonant structure absorbing layer are in the C-band, and the microwaves absorbed by the second microwave resonant structure absorbing layer are in the Ku-band, and the microwave resonant absorption efficiency of both layers is greater than or equal to 0.

9. The stealth material is a microwave resonant structure absorption layer, which is made of raw rubber with added indium tin oxide, zinc aluminum oxide, graphite sheets or iron fiber absorbers. The stealth material is in the frequency range between C-band and Ku-band, and the electromagnetic wave reflectivity R≤-12dB. The stealth material is rolled into sheets by repeatedly rolling the blocky or lumpy raw rubber stealth material into sheets using a kneader; the stealth material sheet is cut using a blade tool according to the unfolded shape of the long airfoil wedge outer edge stealth component, and the missing material areas are cut and supplemented; the stealth material is pre-formed by stacking the first layer of microwave resonant structure absorption layer on top and the second layer of microwave resonant structure absorption layer on the bottom, and the two layers are stacked to obtain the stealth material blank of the long airfoil wedge outer edge stealth component; In step (3), the stealth material blank of the long-wing-shaped wedge stealth component is placed into the core mold, and the stealth material blank of the long-wing-shaped wedge stealth component is placed on the core mold according to the shape of the core mold; in the mold closing and vulcanization molding, the core mold with the stealth material blank of the long-wing-shaped wedge stealth component is placed in the lower mold through the positioning pin, and pressure is applied by the press to close the mold and vulcanize. The mold temperature is set to 130℃-135℃. When the temperature rises from 90℃ to within 110℃, the molding pressure is increased to 3MPa, and the pressure is kept so as not to drop before demolding. The temperature is kept at 130℃-135℃ for 4 hours, and then naturally cooled and demolded to obtain the long-wing-shaped wedge stealth component. In step (4), the long airfoil wedge outer edge stealth component is bonded by adhesive bonding. The bonding surfaces of the long airfoil wedge outer edge stealth component and the metal substrate airfoil wedge outer edge are wiped clean and a layer of epoxy adhesive is evenly applied. The airfoil wedge outer edge stealth component is bonded and applied in a continuous manner according to the reserved groove on the metal substrate airfoil wedge outer edge, with the wingtip as the reference point. During vacuum compaction and curing, the stealth component on the outer edge of the airfoil wedge and the metal substrate are bonded together and then vacuumed and pressurized for curing. During vacuuming, the pressure inside the vacuum bag is below -0.085MPa and the vacuuming time is more than 4 hours. After finishing, the bonding area of ​​the cured resonant long airfoil wedge outer edge stealth component is smoothly transitioned, with a step difference of less than 0.2mm in the flight direction. The overall structure of the bonded long airfoil wedge outer edge stealth component meets the aerodynamic requirements and presents a streamlined shape, thus obtaining the resonant long airfoil wedge outer edge stealth structure component.

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