CN114193863B - Preparation method of invisible airfoil surface part - Google Patents
Preparation method of invisible airfoil surface part Download PDFInfo
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- CN114193863B CN114193863B CN202111528509.XA CN202111528509A CN114193863B CN 114193863 B CN114193863 B CN 114193863B CN 202111528509 A CN202111528509 A CN 202111528509A CN 114193863 B CN114193863 B CN 114193863B
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- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
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- B32B27/00—Layered products comprising a layer of synthetic resin
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- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
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- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/38—Layered products comprising a layer of synthetic resin comprising epoxy resins
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- B32—LAYERED PRODUCTS
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- B32B27/00—Layered products comprising a layer of synthetic resin
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- B32B33/00—Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
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- B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
- B32B37/06—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the heating method
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
- B32B37/10—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the pressing technique, e.g. using action of vacuum or fluid pressure
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- B64—AIRCRAFT; AVIATION; COSMONAUTICS
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- B64F5/00—Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
- B64F5/10—Manufacturing or assembling aircraft, e.g. jigs therefor
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- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/10—Inorganic fibres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/10—Inorganic fibres
- B32B2262/101—Glass fibres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/10—Inorganic fibres
- B32B2262/106—Carbon fibres, e.g. graphite fibres
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
- B32B2307/212—Electromagnetic interference shielding
Abstract
The invention discloses a preparation method of a stealth airfoil part, wherein the stealth airfoil part is composed of a dielectric layer material, a wave-absorbing functional material and a shielding bottom layer material, and the wave-absorbing functional material is rapidly detected before the stealth airfoil part is manufactured and molded. The device used for the test comprises a reflectivity field measuring instrument, a standard reference medium laminate and a shielding bottom plate, and the test is carried out according to the following steps: the wave-absorbing functional material, the standard reference dielectric plate and the shielding bottom plate form a multilayer structure, and the paving sequence of the wave-absorbing functional material is required to be consistent with the actual paving sequence of the stealth airfoil part. The standard reference medium plate is prepared by adopting a medium layer material, and the thickness of the standard reference medium plate is consistent with the designed thickness of the medium layer material in the actual paving layer. And (3) compacting the wave-absorbing functional material on the outer surface of the multilayer combined structure by a reflectivity field measuring instrument to perform reflectivity test, and judging whether the stealth performance of the wave-absorbing functional material after being used for forming the stealth airfoil part can reach the expected index according to whether the test result R reaches the standard.
Description
Technical Field
The invention belongs to the technical field of radar stealth airfoil parts, and relates to a stealth airfoil part preparation method based on material reflectivity rapid detection. The technical scheme can be applied to radar stealth designs of airplane/missile wings, empennages and control surfaces of various stealth aircrafts, and is also suitable for design of stealth structural parts with complex shapes, such as air inlet channels, tail nozzles and the like.
Background
The airfoil is one of main radar scattering sources of the aircraft, and in order to reduce radar echoes of the aircraft and improve the stealth performance of the aircraft, a multilayer wave-absorbing composite material with broadband wave-absorbing characteristics needs to be adopted.
China invention patents ' a honeycomb sandwich graphene stealth front edge and a processing method thereof ' (application number: CN 202011162303.5) ' a stealth/force-bearing type structure airfoil ' (application number: CN201710817592. X) ' a wave-absorbing composite material aircraft part and a preparation method thereof ' (application number: CN 201910976298.2) ' disclose wave-absorbing structure parts in different forms, but the wave-absorbing structure part methods can not control stealth performance in advance before part preparation and molding, and have the risk of scrapping due to unqualified stealth performance after preparation and molding.
In the aspect of stealth performance detection, GJB 5022-2001, namely an indoor field scaling model radar scattering cross section testing method, provides a radar scattering cross section method for measuring scaling or full-size targets under an indoor field condition, and is only suitable for targets or parts which are prepared and formed; two common methods for testing the reflectivity of the wave-absorbing material are provided in GJB2038A, namely a bow rack method and a darkroom RCS method, and during testing by the method, the prepared wave-absorbing material is required to be cut into flat pieces with standard specifications for testing. Peng Gang and so on, in the chinese utility model patent application document "a handheld radar wave-absorbing coating reflectivity field measuring instrument" (application number 201620741587.6), a method for measuring the reflectivity of a specific part of a material with any plane shape is disclosed. It is characterized by that the microwave probe is tightly attached to the surface of prepared solid object to be tested to make test. It can be seen that the existing various testing methods can only be performed on a cured material flat plate or a material part, and for the wave-absorbing composite material comprising a plurality of functional layers, the wave-absorbing performance of the cured material cannot be rapidly and directly tested before the composite material is formed. Moreover, even after the material is cured, the method cannot perform reflectivity detection on the inner surface of the cavity that cannot be touched by the antenna aperture surface.
The Chinese invention patent 'a broadband wave-absorbing force-bearing composite material and a preparation method thereof' (No. ZL 201520617711.8) discloses a preparation method of a wave-absorbing force-bearing composite material, which requires that a wave-absorbing layer material is firstly prepared, then the wave-absorbing layer material is subjected to reflectivity detection, and a material piece is prepared after the wave-absorbing layer material is qualified. The method only refers to the detection of the reflectivity of the wave-absorbing functional layer material, but cannot effectively monitor the overall reflectivity performance of the wave-absorbing functional layer material compounded with the medium material, and the broadband reflectivity of the wave-absorbing material can be detected only after the wave-absorbing material is completely cured to prepare a sample according to a conventional method.
Disclosure of Invention
The invention provides a stealth airfoil part preparation method based on material reflectivity rapid detection, which is characterized in that a standard reference dielectric plate is prepared in advance, a reflectivity field tester is adopted to perform a reflectivity rapid test method on a wave-absorbing function layer material in an overlapping manner before a multi-layer composite material is cured and formed, the integral reflectivity performance after the multi-layer material is compounded is rapidly obtained, the stealth performance is rapidly obtained before the complex wave-absorbing structure part is cured and formed, and the risk that the wave-absorbing structure part is scrapped due to unqualified stealth performance after being prepared and formed is avoided.
The technical scheme of the invention is as follows:
a preparation method of a stealth airfoil part, wherein the airfoil adopts a multilayer wave-absorbing composite material at the edge part, the multilayer wave-absorbing composite material consists of two or more stealth functional layers and a shielding bottom layer, and each stealth functional layer material has different electromagnetic parameters, and the preparation method comprises the following steps: before the layering of the multi-layer wave-absorbing composite material is cured, each layer of the multi-layer material is respectively and independently subjected to reflectivity detection by the following method;
in the multi-layer wave-absorbing composite material, the number of the invisible functional layer except the shielding bottom layer is n, and the marks are x from outside to inside in sequence i Layer, i =1,2, … …, n, for x i The reflectivity properties of the layer material were tested non-destructively as follows:
the first step is as follows: preparing a standard reference plate material
Selecting standard materials with strictly controlled thickness and electrical property as standard reference dielectric slabs, requiring the standard reference dielectric slabs to be tightly attached to each other, and respectively defining the standard reference dielectric slabs as y from outside to inside according to the layering sequence j Layer, j =1,2, … …, n;
each of y is required j The shape of the reference medium plate is the size of a standard RAM plate, and the test is carried out according to a standard test method in the national military standard 2038A;
the second step: x in the material to be measured i Layer material replacing y in reference plate material i The layer material is combined with other layer materials, and the layering sequence is as follows: "y" is 1 +y 2 +…+y i-1 +x i +y i+1 +…+y n + a shield bottom layer ";
the third step: for the product obtained in the second step containing x i The multilayer combined structure of the layer materials adopts field reflectivity measuring equipment to test the reflectivity, and x is judged according to the test result i Whether the wave-absorbing performance of the layer material is qualified or not;
and (3) after the electrical property detection of each layer of material is finished according to the steps, screening the stealth functional layer material of which the electrical property meets the requirement of the part, and layering in a mould according to a conventional method to finish the processing and forming of the stealth part.
Preferably, the size shape of each standard reference medium plate material is a square meeting the test standard, and the high-precision test is completed in a microwave dark room.
Preferably, the standard reference medium plate is completely cured before testing and has a determined thickness, and the thickness has two specifications of D1 and D2, wherein D1 is the upper thickness limit of the medium layer material in the actual molding process, and D2 is the lower thickness limit of the medium layer material in the actual molding process; during testing, the reference dielectric plate with the thickness of D1 and D2 and the wave-absorbing functional material are combined respectively, reflectivity results R1 and R2 are obtained through testing, if R1 and R2 both meet expected reflectivity indexes, the wave-absorbing functional material is determined to be qualified in performance, and screening is passed.
Preferably, the plane dimensions of the standard reference dielectric plate and the shielding bottom plate are larger than the dimension of the aperture surface of the testing antenna of the reflectivity field measurement equipment, and the plane dimension of the material to be tested is larger than the plane dimension of the standard reference dielectric plate.
Preferably, the standard reference dielectric plate and the shielding bottom plate are synchronously moved, and the reflectivity test is carried out on the wave absorption functional material point by point at any position.
Preferably, the airfoil adopts a multilayer wave-absorbing composite material at the edge part, the multilayer wave-absorbing composite material consists of two or more stealth functional layers and a layer of shielding bottom layer material, and each stealth functional layer material has different electromagnetic parameters, and the preparation method is characterized in that: before the spreading layer of the multi-layer wave-absorbing composite material is cured, respectively and independently detecting the reflectivity of each layer of the multi-layer material according to the following method;
in the multilayer wave-absorbing composite material, the number of the invisible functional layer except the shielding bottom layer is n, and the marks are x from outside to inside in sequence i Layer i =1,2, … …, n, for x i The reflectivity properties of the layer material were tested non-destructively as follows:
the first step is as follows: determining structure thickness
According to a conventional composite material forming process, forming a composite material part with a complex shape, measuring the structural thickness [ D2, D1] of a stealth functional layer outside a xi layer material on the material after dissection, and measuring the structural thickness range [ D2, D1] inside the xi layer material;
the second step is that: preparing a standard reference plate material
Selecting each layer of standard material with strictly controlled thickness and electrical property as a standard reference dielectric slab, requiring the standard reference dielectric slabs to be tightly attached to each other, and respectively defining each standard reference dielectric slab as y from outside to inside according to the layering sequence j Layer, j =1,2, … …, n;
each of y is required j The shape of the reference medium plate is the size of a standard RAM plate, and the test is carried out according to a standard test method in the national military standard 2038A;
the third step: for core in the structureStealth function x i The layer materials were separately tested for reflectivity
a. Preparing a standard reference medium laminate with the thickness specification of D1, wherein the layering sequence is' y 1+ y 2+.. y i-1 ", the whole is solidified after the layering is finished; preparing a standard reference medium laminate with the thickness specification of D2, wherein the layering sequence is' y 1+ y 2+.. y i-1 ", after the layering is finished, the whole body is solidified and then is used as two dielectric layers I for standby;
b. preparing a standard reference medium laminate with the thickness specification of d1, wherein the laminating sequence is' y i+1 +…+y n + shielding the bottom layer, and integrally curing after layering is finished; preparing a standard reference medium laminate with the thickness specification of d2, wherein the laminating sequence is' y i+1 +…+y n + a shielding bottom layer ", and taking the layer as two dielectric layers II for standby after the overall solidification is finished;
the fourth step: screening of material electrical properties
a. X to be measured i The layer material is combined with the dielectric plate I and the dielectric plate II to obtain' y 1 +y 2 +…+y i-1 +x i +…+y i+1 +y n A layer structure of the shielding bottom layer is adopted, and local electrical property detection is carried out by adopting reflectivity field measurement equipment in an assembled state;
during testing, a dielectric plate I with the thickness of D1 and a dielectric plate II with the thickness of D1 are selected to be matched for use, and the reflectivity R1 is tested;
during testing, a dielectric plate I with the thickness of D2 and a dielectric plate II with the thickness of D2 are selected to be matched for use, and the reflectivity R2 is tested;
b. when the reflectivity R1 and the reflectivity R2 of the material are qualified, the reflectivity of the prepared structural member with the complex curved surface appearance is qualified;
repeating the steps to complete the electrical property screening of each layer of material in the structure
And finally, selecting the screened materials to complete the preparation and molding of the structural member according to a conventional method.
The invention has the beneficial effects that:
the beneficial effects of the invention are embodied in three aspects:
(1) The method overcomes the defect that the stealth performance of the existing complex wave-absorbing structure part preparation method cannot be obtained before preparation and forming, reduces the risk that the stealth performance of the part after forming is not up to standard and the wave-absorbing structure part is wasted, and ensures the stealth performance of the part before the wave-absorbing structure part is prepared and formed.
(2) The rapid detection method for the reflectivity of the material can reflect the intrinsic reflectivity characteristics of the material of the wave-absorbing functional layer to be detected in the multilayer material, can completely predict the reflectivity index after forming by matching with the reference dielectric slabs with different thickness standards, and avoids the misjudgment risk of the reflectivity performance of the test panel caused by incomplete coverage of the reference after the selection of a single reference in the existing detection method.
(3) For complex parts such as aircraft complex curved surface shape stealth airfoil surface parts and the like, because the molded surface is difficult to meet the requirement of direct reflectivity test, the method provides an important method for testing the reflectivity of materials in various regions on the parts. The method is also suitable for preparing typical wave-absorbing structural components with complex shapes, such as air inlet channels, cabin sections and the like.
Drawings
The total number of the figures in the specification is 3.
FIG. 1 is a schematic view of a wave-absorbing material layer of a stealth airfoil edge with a complex appearance;
FIG. 2 is a schematic diagram of the detection of the reflectivity of a wave-absorbing functional layer made of a double-layer material;
FIG. 3 is a schematic diagram of the detection of the reflectivity of the wave-absorbing functional layer by using a multi-layer material component.
In the figure, 1-measured material, 2-reflectivity on-site measuring instrument antenna, 3-outer standard reference material plate, 4-shielding bottom plate and 5-inner reference material plate.
Detailed Description
The present invention is further described with reference to the following specific embodiments.
Example 1: preparation method of empennage surface adopting glass fiber reinforced plastic, co-curing wave-absorbing patch and shielding bottom layer structure
In the structure, the electrical property detection needs to be respectively carried out on the glass fiber reinforced plastic material and the co-cured wave-absorbing patch material before forming, and the specific preparation method comprises the following steps:
the first step is as follows: determining wave-absorbing tail structure layering thickness
Glass fiber cloth is adopted as a medium layer material, a co-curing wave-absorbing patch is adopted as a wave-absorbing function layer material, a single-layer carbon fiber cloth is adopted as a shielding layer and is laid on a dimensional surface in the tail wing, epoxy resin is applied among layers, the wave-absorbing tail wing is prepared and molded according to an autoclave molding process, anatomical measurement is carried out on the wave-absorbing tail wing, the structure thickness of the medium layer is obtained (0.9mm and 1.1mm), and the structure thickness range of the wave-absorbing function layer is measured (1.5mm and 1.7mm);
the second step is that: preparation of wave-absorbing patch, standard reference medium laminate and shielding bottom plate
a. Laying glass fiber cloth, applying epoxy resin between layers, and pressing to obtain standard reference medium laminate with thickness of 0.9mm and 1.1mm and plane size of 180mm × 180mm by autoclave molding process;
b. preparing wave-absorbing patches with thickness specifications of 1.5mm and 1.7mm respectively for later use, wherein the wave-absorbing patches are longer than 1m and wider than 20cm according to actual needs;
c. adopting carbon fiber cloth laying, and applying epoxy resin to prepare the shielding bottom plate with the plane size of 180mm multiplied by 180 mm.
The third step: rapid detection of material reflectivity
a. And (3) rapidly detecting the reflectivity of the wave-absorbing patch: placing a shielding bottom plate, a wave-absorbing patch and a standard reference medium laminate with the thickness specification of 0.9mm from bottom to top in sequence, and testing by using a reflectivity field tester to obtain the reflectivity of-8.7 dB; and replacing the standard reference medium laminate with the thickness specification of 0.9mm with the standard reference medium laminate with the thickness rule of 1.1mm, and repeating the reflectivity test to obtain the reflectivity of-8.9 dB. And judging the wave-absorbing patch to be qualified according to the reflectivity result meeting the requirement of less than or equal to-8.5 dB.
b. And (3) quickly detecting the reflectivity of the glass fiber cloth: the glass fiber cloth is used as a material to be tested, a shielding bottom plate, a wave-absorbing patch with the thickness specification of 1.5mm and the glass fiber cloth are sequentially placed from bottom to top, and a reflectivity-8.6 dB is obtained by testing with a reflectivity field tester; and replacing the wave-absorbing patch with the thickness specification of 1.5mm with a wave-absorbing patch with the thickness rule of 1.7mm, and repeating the reflectivity test to obtain the reflectivity of-9.0 dB. And judging that the glass fiber cloth is qualified according to the reflectivity result meeting the requirement of less than or equal to-8.5 dB.
The fourth step: preparation of wave-absorbing structure empennage
Cutting glass fiber cloth, wave absorbing cloth and carbon fiber cloth according to the shape of the tail wing. And sequentially laying carbon fiber cloth, wave-absorbing patches and glass fiber cloth with preset thicknesses in a die from bottom to top, applying epoxy resin between layers, and preparing according to an autoclave molding process to obtain the wave-absorbing structure empennage.
Example 2 example 1: preparation method of empennage surface adopting structure of quartz fiber reinforced composite material, wave-absorbing cloth and shielding bottom layer
In this structure, the wave-absorbing cloth material is the key point of detection, and according to the consideration of process error, the wave-absorbing cloth material is required to be able to cooperate with the quartz fiber reinforced composite material within the reasonable deviation range of thickness to realize the broadband wave-absorbing characteristic:
the first step is as follows: determining stealth airfoil leading edge structure layer thickness
Adopting quartz fiber cloth as a medium layer material, adopting wave-absorbing cloth as a wave-absorbing function layer material, applying polyurethane resin between layers, completing the preparation and molding of the front edge of the invisible airfoil surface according to a compression molding process, and carrying out anatomical measurement on the front edge of the invisible airfoil surface to obtain the structural thickness of the medium layer [1.9mm,2.1mm ];
the second step is that: preparation of standard reference medium laminate and shielding bottom plate
Adopting quartz fiber cloth layers, applying polyurethane resin between layers, and pressing to obtain standard reference medium laminate with thickness of 1.9mm and 2.1mm and plane size of 180mm × 180mm by compression molding process;
the third step: rapid detection of reflectivity of wave-absorbing cloth material
a. And (3) rapidly detecting the reflectivity of the wave-absorbing cloth: placing a standard reference medium laminate with the thickness specification of 1.9mm, wave absorption cloth to be tested and a shielding bottom layer material in sequence from top to bottom, and testing by adopting a reflectivity field tester to obtain the reflectivity of a multi-frequency point; and replacing the standard reference medium laminate with the thickness specification of 1.9mm with the standard reference medium laminate with the thickness rule of 2.1mm, and repeating the reflectivity test to obtain the multi-frequency point reflectivity. And judging whether the wave absorption cloth is qualified or not according to the reflectivity result requirement.
The fourth step: stealth airfoil leading edge preparation
Cutting quartz fiber cloth, wave-absorbing cloth materials and carbon fiber cloth according to the shape of the wing front edge. Sequentially laying carbon fiber cloth and wave-absorbing cloth with preset thickness in a mold from bottom to top, applying polyurethane resin between layers, and preparing according to a compression molding process to obtain the hidden airfoil leading edge.
In the structure, two layers of wave-absorbing cloth materials are the key points of detection, technological errors need to be considered, the wave-absorbing cloth materials and quartz fiber reinforced composite materials with reasonable thickness deviation range can be matched to realize broadband wave-absorbing characteristics, and electrical property detection is carried out on two wave-absorbing layers respectively according to preparation needs.
The first step is as follows: determining stealth airfoil leading edge structure thickness
Quartz fiber cloth is used as a medium layer material, uncured wave-absorbing cloth with a conductive coating shielding bottom layer is used as a wave-absorbing function layer material, polyurethane resin is applied among layers, the preparation and molding of the front edge of the invisible airfoil surface are completed according to a compression molding process, the front edge of the invisible airfoil surface is dissected and measured to obtain the thickness of the medium layer structure [0.8mm and 1.2mm ], and the thickness ranges of two wave-absorbing layers in the structure are measured to be a first layer [0.8mm and 1.0mm ] and a second layer [0.3mm and 0.4mm ] respectively;
the second step: preparation of wave absorbing cloth, standard reference medium laminate and shielding bottom plate
a. Laying quartz fiber cloth, applying polyurethane resin between layers, and pressing to obtain standard reference medium laminate with thickness of 0.8mm and 1.2mm and plane size of 300mm × 300mm by compression molding;
b. preparing the wave-absorbing cloth 1 with the thickness specifications of 0.8mm and 1.0mm respectively and the plane size of 300mm multiplied by 300mm, and determining the performance of the wave-absorbing cloth to be qualified for later use through a darkroom reflectivity test;
c. preparing the wave-absorbing cloth 2 with the thickness specifications of 0.3mm and 0.4mm respectively and the plane size of 300mm multiplied by 300mm, and determining the performance to be qualified for later use through a darkroom reflectivity test;
the third step:
a. and (3) detecting the electrical property of the wave absorbing layer 1:
a shielding bottom layer, wave-absorbing cloth 2 with the thickness of 0.3mm, a wave-absorbing layer 1 material with infinite length to be tested and a standard reference medium laminate with the thickness specification of 0.8mm are sequentially arranged from bottom to top, and a reflectivity field tester is adopted to test to obtain a reflectivity lower than-10 dB;
a shielding bottom layer, wave-absorbing cloth 2 with the thickness of 0.4mm, a wave-absorbing layer 1 material with infinite length to be tested and a standard reference medium laminate with the thickness specification of 1.2mm are sequentially arranged from bottom to top, and a reflectivity field tester is adopted to test to obtain a reflectivity lower than-10 dB;
and judging that the wave absorption cloth 1 is qualified according to the reflectivity result meeting the requirement of less than or equal to-9 dB.
a. And (3) detecting the electrical property of the wave-absorbing layer 2:
placing a shielding bottom layer, a wave-absorbing cloth 2 with infinite length to be tested, a standard wave-absorbing layer 1 material with the thickness of 0.8mm and a standard reference medium laminate with the thickness specification of 0.8mm in sequence from bottom to top, and testing by using a reflectivity field tester to obtain the reflectivity of a multi-frequency point;
placing a shielding bottom layer, a wave-absorbing cloth 2 with infinite length to be tested, a standard wave-absorbing layer 1 material with the thickness of 1.0mm and a standard reference medium laminate with the thickness specification of 1.2mm in sequence from bottom to top, and testing by using a reflectivity field tester to obtain the reflectivity of a multi-frequency point;
and judging that the wave absorption cloth 2 is qualified according to the reflectivity result meeting the requirement of less than or equal to-8 dB.
The fourth step: stealth airfoil leading edge preparation
Cutting quartz fiber cloth and wave-absorbing cloth materials according to the shape of the wing front edge. And sequentially paving carbon fiber cloth and wave-absorbing cloth with preset thicknesses in a mould from bottom to top, applying polyurethane resin between layers, and preparing according to a compression molding process to obtain the stealth airfoil.
Claims (5)
1. A preparation method of a stealth airfoil part is characterized in that the airfoil adopts a multilayer wave-absorbing composite material at the edge part, the multilayer wave-absorbing composite material consists of two or more stealth functional layers and a shielding bottom layer, and each stealth functional layer material has different electromagnetic parameters: before the spreading layer of the multi-layer wave-absorbing composite material is cured, respectively and independently detecting the reflectivity of each layer of the multi-layer material according to the following method;
in the multi-layer wave-absorbing composite material, the number of the invisible functional layer except the shielding bottom layer is n, and the marks are sequentially from outside to insidex i Layer i =1,2, … …, n, for the secondx i The reflectivity properties of the layer material were tested non-destructively as follows:
the first step is as follows: preparing a standard reference plate material
Selecting standard materials with strictly controlled thickness and electrical property as standard reference dielectric slabs, requiring the standard reference dielectric slabs to be tightly attached to each other, and defining the standard reference dielectric slabs as standard reference dielectric slabs from outside to inside according to the layering sequencey j Layer, j =1,2, … …, n;
each of y is required j The shape of the reference medium plate is the size of a standard RAM plate, and the test is carried out according to a standard test method in the national military standard 2038A;
the second step: in the material to be measuredx i Layer material replacing y in reference plate material i The layer material is combined with other layer materials, and the layering sequence is as follows: "y 1 +y 2 +…+y i-1 +x i +y i+1 +…+y n +Shielding bottom layer ";
the third step: to the contents obtained in the second stepx i The multilayer combined structure of the layer materials adopts field reflectivity measuring equipment to test the reflectivity, and judges the reflectivity according to the test resultx i Whether the wave-absorbing performance of the layer material is qualified or not;
after the electrical property detection of each layer of material is completed according to the steps, screening the stealth functional layer material with the electrical property meeting the component requirement, and layering in a mould according to a conventional method to complete the processing and forming of the stealth component;
the standard reference medium plate is completely solidified before testing and has a determined thickness, and the thickness of the standard reference medium plate has two specifications D1 and D2, wherein D1 is the upper limit of the thickness of the medium layer material in the actual forming process, and D2 is the lower limit of the thickness of the medium layer material in the actual forming process; during testing, the reference dielectric plate with the thickness of D1 and D2 and the wave-absorbing functional material are combined respectively, reflectivity results R1 and R2 are obtained through testing, if the reflectivity results R1 and R2 meet the expected reflectivity index, the wave-absorbing functional material is determined to be qualified in performance, and screening is passed.
2. A method of making a stealth airfoil component according to claim 1, wherein: the size and shape of each standard reference dielectric plate material are square which meet the test standard, and the high-precision test is completed in a microwave dark room.
3. A method of making a stealth airfoil component according to claim 2, wherein: the plane size of the standard reference dielectric plate and the shielding bottom plate is larger than the plane size of the opening surface of the testing antenna of the reflectivity field measuring equipment, and the plane size of the material to be tested is larger than the plane size of the standard reference dielectric plate.
4. A method of making a stealth airfoil component according to claim 3, wherein: and (3) performing reflectivity test point by point at any position on the wave absorption functional material by synchronously moving the standard reference dielectric plate and the shielding bottom plate.
5. A preparation method of a stealth airfoil part is characterized in that the airfoil adopts a multilayer wave-absorbing composite material at the edge part, the multilayer wave-absorbing composite material consists of two or more stealth functional layers and a layer of shielding bottom layer material, and each stealth functional layer material has different electromagnetic parameters: before the spreading layer of the multi-layer wave-absorbing composite material is cured, respectively and independently detecting the reflectivity of each layer of the multi-layer material according to the following method;
in the multi-layer wave-absorbing composite material, the number of the invisible functional layer except the shielding bottom layer is n, and the marks are sequentially from outside to insidex i Layer i =1,2, … …, n, for the secondx i The reflectivity properties of the layer material were tested non-destructively as follows:
the first step is as follows: determining structure thickness
According to the conventional composite material forming process, the forming of the composite material part with the complex shape is completed, and after dissection, the material is measuredx i Structural thickness of stealth functional layer outside layer material [ D2, D1]Measuring the structural thickness range [ d2, d1] inside the xi layer material]；
The second step is that: preparing a standard reference plate material
Selecting standard materials with strictly controlled thickness and electrical property as standard reference dielectric slabs, requiring the standard reference dielectric slabs to be tightly attached to each other, and defining the standard reference dielectric slabs as standard reference dielectric slabs from outside to inside according to the layering sequencey j Layer, j =1,2, … …, n;
each of y is required j The shape of the reference medium plate is the size of a standard RAM plate, and the test is carried out according to a standard test method in the national military standard 2038A;
the third step: hiding core in structurex i The layer materials were separately tested for reflectivity
a. Preparing a standard reference medium laminate with the thickness specification of D1, wherein the layering sequence is' y 1+ y 2+.. y i-1 ", the whole is solidified after the layering is finished; preparing a standard reference medium laminate with the thickness specification of D2, wherein the layering sequence is' y 1+ y 2+.. y i-1 After layering is finished, the whole body is solidified to be used as two dielectric layers I for standby;
b. to prepare thickA standard reference medium laminate with the specification of d1, the laminating sequence of which is'y i+1 +…+y n +Shielding the bottom layer, and integrally curing after layering is finished; a standard reference dielectric laminate with thickness specification d2 was prepared with a lay-up sequence "y i+1 +…+y n +A shielding bottom layer which is used as two dielectric layers II for standby after the overall solidification of the layer is finished;
the fourth step: electric property screening of material
a. To be testedx i Combining the layer material with dielectric sheet I and dielectric sheet II to obtain "y 1 +y 2 +…+y i-1 +x i +…+y i+1 + y n +Shielding a layer structure of a bottom layer, and detecting local electrical property by using a reflectivity field measurement device in an assembled state;
during testing, a dielectric plate I with the thickness of D1 and a dielectric plate II with the thickness of D1 are selected to be matched for use, and the reflectivity R1 is tested;
during testing, a dielectric plate I with the thickness of D2 and a dielectric plate II with the thickness of D2 are selected to be matched for use, and the reflectivity R2 is tested;
b. when the reflectivity R1 and the reflectivity R2 of the material are qualified, the reflectivity of the prepared structural member with the complex curved surface appearance is qualified;
repeating the steps to complete the electrical property screening of each layer of material in the structure
And finally, selecting the screened materials to complete the preparation and molding of the structural member according to a conventional method.
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