Conical wave-transparent hood and preparation method thereof

Abstract

According to the conical wave-transparent hood and the preparation method thereof, the conical wave-transparent hood adopts a quartz fiber honeycomb sandwich composite material as a main body structure, the overall structure weight is reduced, meanwhile, the wave-transparent performance of the hood is improved, the tail end is reinforced by adopting a quartz fiber composite material laminated structure, and the assembly requirement is met; the conical head area is of a conical structure, the conical head end is defined as the original point, the direction from the conical head end to the conical tail end is taken as the X-axis direction, the conical surface line shape of the conical head area meets the condition that Y is equal to 75.3 (X / 300) 0.7, the aerodynamic layout is excellent, and the range of the aircraft is increased; the wave transmission rate of the conical wave-transmitting head cover is larger than 90% when the workpiece is in the frequency band of 2GHz-24GHz and the incident angle is within the range of + / -60 degrees. According to the conical wave-transparent hood, the problem that an existing hood cannot have high wave-transparent performance under the conditions of light weight and high strength is solved, the cost is low, the manufacturing period is short, and the process implementation difficulty is low.

Description

Technical Field

[0001] The present application relates to the technical field of composite material molding, and in particular to a conical wave-transmitting head cover and a preparation method thereof. Background Art

[0002] As a structural component of a missile, the wave-transparent hood plays an important role in the missile. On the one hand, the function of the wave-transparent hood is to maintain the aerodynamic shape during flight and protect the payload inside the hood from the influence of the external natural environment and aerodynamic scouring; on the other hand, it is a component of the wireless homing guidance system, serving as a channel for sending and receiving electromagnetic wave signals to ensure normal communication with the outside world. With the continuous advancement of aerospace technology, material forming technology and the transformation of modern warfare modes, missiles are gradually developing in the direction of high-speed flight and precision guidance, and the performance of the wave-transparent hood will directly affect the flight performance, combat performance and hit performance of the missile.

[0003] The performance of the hoods reported so far cannot meet the requirements of new guided aircraft. The hoods used for missiles are mainly made of carbon fiber, which has only high mechanical properties but does not meet the requirements of wave transmission performance; the hoods made by 3D printing have poor high temperature resistance, are prone to aging, and are prone to surface deformation under aerodynamic loads; the hoods made of alloys have very complex structures and cannot meet the requirements of high performance and light weight in my country's aircraft upgrade projects. Summary of the invention

[0004] In order to solve the technical problem in the prior art that the wave-transparent head cover used for missiles cannot have both light weight and high strength and high wave transmittance, the present application proposes a conical wave-transparent head cover and a preparation method thereof, so as to effectively improve the wave-transmitting performance of the aircraft wave-transparent head cover, while reducing its weight to meet the demand for lightweight development of the aircraft.

[0005] In order to achieve the above-mentioned purpose, this application adopts the following technical solutions:

[0006] A conical wave-transmitting head cover, comprising a conical head area and a reinforced tail area;

[0007] The conical head region includes an inner skin layer, an inner film layer, a honeycomb sandwich layer, an outer film layer and an outer skin layer which are arranged in sequence from the inside to the outside, wherein the honeycomb sandwich layer is made of aramid honeycomb panels;

[0008] The conical head area is a conical structure, including a conical head end and a conical tail end. The conical head end is taken as the origin, and the direction from the conical head end to the conical tail end is defined as the X-axis direction. Then the conical surface linear setting of the conical head area satisfies Y=75.3(X / 300) 0.7 ;

[0009] The reinforced tail region is an annular structure and is arranged at the conical tail end of the conical head region.

[0010] Furthermore, the inner skin layer and the outer skin layer are both made of quartz fiber cyanate prepreg.

[0011] Furthermore, the inner adhesive film layer and the outer adhesive film layer are both made of cyanate adhesive film.

[0012] Furthermore, the splicing is performed by inserting core cells into each other.

[0013] Furthermore, the heading of the conical wave-transmitting head cover is defined as the paving direction of 0°, and the paving method of the conical head area is: [(±45) / (0 / 90)2 / (±45) / (0 / 90) / cyanate ester film / aramid honeycomb] S The whole layer, the paving method of the reinforced tail area is [(±45) / (0 / 90)2 / (±45) / (0 / 90)7 / (0 / 90)] S .

[0014] A method for preparing a conical wave-transmitting head cover comprises the following steps:

[0015] S1. Laying quartz fiber cyanate prepreg in a female mold to obtain an outer skin layer, and pre-vacuuming to make the outer skin layer fit closely with the female mold;

[0016] S2, after laying the outer film layer on the outer skin layer, laying the honeycomb sandwich layer on the outer film layer; wherein the honeycomb sandwich layer is made of aramid honeycomb panels;

[0017] S3, laying an inner film layer on the honeycomb sandwich layer and then laying an inner skin layer on the inner film layer to obtain a preform;

[0018] S4, bagging the preform, solidifying and molding it through an autoclave, and demoulding it to obtain the conical wave-transmitting head cover.

[0019] Furthermore, the splicing in step S2 is performed by inserting core cells into each other.

[0020] Furthermore, the curing medium used in the autoclave curing molding process is nitrogen.

[0021] Furthermore, during the autoclave curing and molding process, the preform bag is completely vacuumed.

[0022] Furthermore, the autoclave curing molding process is as follows:

[0023] A. When starting to cure, the temperature in the autoclave is raised to 130°C ± 3°C at a rate of no more than 2°C / min, and the temperature is kept for 240 to 245 minutes. When the temperature in the autoclave reaches 130°C ± 3°C, the pressure in the autoclave is increased to 2.5 bar ± 0.3 bar.

[0024] B. After completing step A, increase the temperature in the autoclave to 180°C ± 5°C and keep it warm for 180 to 185 minutes, with the heating rate not exceeding 1°C / min;

[0025] C. After completing step B, the temperature in the autoclave is reduced to below 60°C, wherein the cooling rate does not exceed 2°C / min;

[0026] D. Release the pressure, cool down and open the autoclave.

[0027] The beneficial effects of this application are:

[0028] The present invention adopts aramid honeycomb panels to form a honeycomb sandwich layer and uses it as the main structure of the conical wave-transmitting head cover, thereby ensuring that the overall weight of the conical wave-transmitting head cover is effectively reduced while having excellent wave-transmitting performance; wherein, in the 2GHz to 24GHz frequency band, within the range of the incident angle of ±60°, the wave transmittance of the present invention is greater than 90%; at the same time, the conical surface line shape of the conical head area of ​​the present invention adopts Y=75.3(X / 300) 0.7 The calculation and setting are carried out in a way that can not only make the conical wave-transparent head cover maintain the shape of the missile, but also bear the aerodynamic load and temperature load, keep the aerodynamic flow field stable and the pressure distribution uniform, etc.

[0029] The paving method of the conical head area of ​​the present application is: [(±45) / (0 / 90)2 / (±45) / (0 / 90) / cyanate film / aramid honeycomb] S The whole layer, among which, the ±45° and 0 / 90 layer design makes the head cover have certain strength and rigidity. The honeycomb reduces the overall weight while improving the wave transmission performance. The paving method of the reinforced tail area is [(±45) / (0 / 90)2 / (±45) / (0 / 90)7 / (0 / 90)] S This paving method enables the reinforced tail area to meet the needs of opening, assembly and connection.

[0030] In the present application, since the main body of the conical wave-transmitting head cover (i.e., the conical head area) is a conical structure, the aramid honeycomb panel needs to be bent when a whole piece of aramid honeycomb panel is used for paving, which will cause serious deformation of the core grid of the aramid honeycomb panel, thereby affecting the overall performance of the conical wave-transmitting head cover. Therefore, the present application adopts the method of paving the aramid honeycomb panel in blocks and splicing them together, which can effectively solve the deformation problem during the paving process; at the same time, the block aramid honeycomb panels are spliced ​​by interlocking the core grids, which can effectively avoid the use of foam glue to bond and affect the product's wave-transmitting performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0032] Figure 1 A schematic diagram of the structure of a conical wave-transmitting head cover provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the ply structure of the conical head region provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the molding die structure provided in an embodiment of the present application;

[0035] Figure 4 This is a test diagram of the wave transmittance of the conical wave-transmitting head cover provided by the embodiment of the present application at different frequencies;

[0036] Description of Figure Numbers:

[0037] Conical head area 1, reinforced tail area 2, inner skin layer 3, inner film layer 4, honeycomb sandwich layer 5, outer film layer 6, outer skin layer 7. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present application will be clearly and completely described below in combination with the technical scheme of the embodiment. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In the description of the present application, the experimental methods, unless otherwise specified, are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from commercial channels.

[0039] The disclosure below provides many different embodiments or examples to implement the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. Those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0040] Example

[0041] The present application embodiment provides a conical wave-transmitting head cover, such as Figure 1 and Figure 2 As shown, it includes a tapered head region 1 and a reinforced tail region 2;

[0042] The conical head region is a conical structure, including a conical head end and a conical tail end. The conical head end is defined as the origin, and the direction from the conical head end to the conical tail end is taken as the X-axis direction. Then, the conical surface linear setting of the conical head region satisfies Y=75.3(X / 300) 0.7 The reinforced tail area is an annular structure and is arranged at the conical tail end of the conical head area.

[0043] The conical head region includes an inner skin layer 3, an inner film layer 4, a honeycomb sandwich layer 5, an outer film layer 6 and an outer skin layer 7 arranged in sequence from the inside to the outside;

[0044] Because the wave transmission performance of the conical wave-transmitting head cover is mainly determined by the dielectric constant and dielectric loss tangent of the raw materials. The larger the dielectric constant, the lower the electromagnetic wave transmission efficiency; the larger the dielectric loss tangent, the more electromagnetic wave loss. Therefore, the inner skin layer and the outer skin layer are both made of quartz fiber cyanate prepreg with a dielectric constant of 3.1 and a dielectric loss tangent of 0.007. This material has a stable and low dielectric constant and dielectric loss tangent, which can ensure good wave transmission performance; the inner film layer and the outer film layer are both made of cyanate film of the same system to ensure the same good wave transmission performance; and the honeycomb sandwich layer is made of aramid honeycomb panels with a dielectric constant of 1.084 and a dielectric loss tangent of 0.0047; while reducing the overall weight of the conical wave-transmitting head cover, it has good wave transmission performance. At the same time, in order to avoid the situation where the wave transmission performance of the product is affected by the use of foam adhesive bonding, the splicing between the aramid honeycomb panels is performed by core-cell interlocking.

[0045] When the conical wave-transmitting head cover is laid, the heading of the conical wave-transmitting head cover is defined as the laying direction of 0°, and the laying method of the conical head area is: [(±45) / (0 / 90)2 / (±45) / (0 / 90) / cyanate ester film / aramid honeycomb] SThe whole ply, ±45°, 0 / 90 ply design makes the hood have certain strength and rigidity. The honeycomb reduces the overall weight while improving the wave transmission performance. The plying method of the reinforced tail area is [(±45) / (0 / 90)2 / (±45) / (0 / 90)7 / (0 / 90)] S This paving method enables the reinforced tail area to meet the needs of opening, assembly and connection.

[0046] A method for preparing the conical wave-transmitting head cover as described above comprises the following steps:

[0047] S1. Lay quartz fiber cyanate prepreg in the female mold to obtain the outer skin layer. The mold is as follows: Figure 3 As shown, pre-vacuum is applied to make the outer skin layer fit tightly with the female mold; the cone head end position corresponding to the cone head area of ​​the cone-shaped wave-transmitting head cover in the female mold should be compacted using auxiliary tools such as a fine scraper to ensure that the outer skin layer and the female mold can fit tightly, thereby ensuring the smoothness of the overall shape of the cone-shaped wave-transmitting head cover.

[0048] S2. After laying the outer film layer on the outer skin layer, lay the honeycomb sandwich layer on the outer film layer; wherein, the honeycomb sandwich layer is made of aramid honeycomb panels; wherein, the splicing is performed by interlocking core cells. Since the main body (i.e., the conical head area) of the conical wave-transmitting head cover is a conical structure, the aramid honeycomb panel needs to be bent when a whole piece of aramid honeycomb panel is used for laying, which will cause serious deformation of the core cell of the aramid honeycomb panel, thereby affecting the overall performance of the conical wave-transmitting head cover. Therefore, the present application adopts the method of block splicing of aramid honeycomb panels for laying, which can effectively solve the deformation during the laying process; at the same time, the block aramid honeycomb panels are spliced ​​by interlocking core cells, which can effectively avoid the situation that the wave-transmitting performance of the product is affected by foam adhesive bonding. At the same time, it should be noted that when paving the honeycomb sandwich layer, the size of the cone head end corresponding to the cone head area of ​​the cone-shaped wave-transmitting head cover in the female mold is too small, and the aramid honeycomb panel cannot be used for normal paving. Therefore, the cone head end can be padded with quartz fiber cyanate prepreg to form a gentle rounded shape, and then the aramid honeycomb panel is placed for paving.

[0049] S3, laying an inner film layer on the honeycomb sandwich layer and then laying an inner skin layer on the inner film layer to obtain a product;

[0050] S4, bagging the product, curing and molding it in an autoclave, and demoulding it to obtain the conical wave-transmitting head cover.

[0051] The curing medium used in the autoclave curing molding process is nitrogen, and the preform bag is fully vacuumed during the autoclave curing molding process. The autoclave curing molding process is as follows:

[0052] A. When starting to cure, the temperature in the autoclave is raised to 130°C ± 3°C at a rate of no more than 2°C / min, and the temperature is kept to cure for 240 minutes; when the temperature in the autoclave rises to 130°C ± 3°C, the pressure in the autoclave is increased to 2.5 bar ± 0.3 bar;

[0053] B. After completing step A, increase the temperature in the autoclave to 180°C ± 5°C and keep it warm for 180 minutes, with the heating rate not exceeding 1°C / min;

[0054] C. After completing step B, the temperature in the autoclave is reduced to below 60°C, wherein the cooling rate does not exceed 2°C / min;

[0055] D. Release the pressure, cool down and open the autoclave.

[0056] Performance testing

[0057] In order to verify the wave transmission performance of the conical wave-transmitting head cover obtained in the above embodiment, the wave transmission performance of the conical wave-transmitting head cover obtained in the above embodiment is tested at different frequencies and different incident angles according to the standard of GJB7954-2012. The test results are as follows: Figure 4 As shown. Figure 4 It can be seen that the conical wave-transmitting head cover obtained in the above embodiment of the present application has a wave transmittance greater than 90% in the frequency band of 2GHz to 24GHz and an incident angle range of ±60°, and its wave transmittance can even reach more than 99% in the low frequency band.

[0058] The conical wave-transparent head cover and its preparation method provided in the embodiments of the present application are introduced in detail above. The principles and implementation methods of the present application are explained in this article by using specific examples. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A conical wave-transmitting head cover, characterized in that: Includes a tapered head area and a reinforced tail area; The conical head region includes an inner skin layer, an inner film layer, a honeycomb sandwich layer, an outer film layer and an outer skin layer which are arranged in sequence from the inside to the outside, wherein the honeycomb sandwich layer is made of aramid honeycomb panels; The conical head region is a conical structure, including a conical head end and a conical tail end. The conical head end is taken as the origin, and the direction from the conical head end to the conical tail end is defined as the X-axis direction. Then the conical surface line shape of the conical head region satisfies Y=75.3(X / 300) 0.7 ; The reinforced tail region is an annular structure and is arranged at the conical tail end of the conical head region.

2. The conical wave-transmitting head cover according to claim 1, characterized in that: The inner skin layer and the outer skin layer are both made of quartz fiber cyanate prepreg.

3. The conical wave-transmitting head cover according to claim 1, characterized in that: The inner adhesive film layer and the outer adhesive film layer are both made of cyanate adhesive film.

4. The conical wave-transmitting head cover according to claim 1, characterized in that: The splicing is performed by inserting core cells into each other.

5. The conical wave-transmitting head cover according to claim 1, characterized in that: The heading of the conical wave-transmitting head cover is defined as the paving direction of 0°, and the paving method of the conical head area is: [(±45) / (0 / 90)2 / (±45) / (0 / 90) / cyanate film / aramid honeycomb] S The whole layer, the paving method of the reinforced tail area is [(±45) / (0 / 90)2 / (±45) / (0 / 90)7 / (0 / 90)] S .

6. A method for preparing a conical wave-transmitting head cover, characterized in that: The steps include: S1. Laying quartz fiber cyanate prepreg in a female mold to obtain an outer skin layer, and pre-vacuuming to make the outer skin layer fit closely with the female mold; S2, after laying the outer film layer on the outer skin layer, laying the honeycomb sandwich layer on the outer film layer; wherein the honeycomb sandwich layer is made of aramid honeycomb panels; S3, laying an inner film layer on the honeycomb sandwich layer and then laying an inner skin layer on the inner film layer to obtain a preform; S4, bagging the preform, solidifying and molding it through an autoclave, and demoulding it to obtain the conical wave-transmitting head cover.

7. The method for preparing the conical wave-transmitting head cover according to claim 6, characterized in that: The splicing in step S2 is performed by inserting core cells into each other.

8. The method for preparing the conical wave-transmitting head cover according to claim 6, characterized in that: The curing medium used in the autoclave curing molding process is nitrogen.

9. The method for preparing the conical wave-transmitting head cover according to claim 6, characterized in that: During the autoclave curing and molding process, the preform bag is fully evacuated.

10. The method for preparing the conical wave-transmitting head cover according to claim 6, characterized in that: The autoclave curing molding process is as follows: A. When starting to cure, the temperature in the autoclave is raised to 130°C ± 3°C at a rate of no more than 2°C / min, and the temperature is kept for 240 to 245 minutes. When the temperature in the autoclave reaches 130°C ± 3°C, the pressure in the autoclave is increased to 2.5 bar ± 0.3 bar. B. After completing step A, increase the temperature in the autoclave to 180°C ± 5°C and keep it warm for 180 to 185 minutes, with the heating rate not exceeding 1°C / min; C. After completing step B, the temperature in the autoclave is reduced to below 60°C, wherein the cooling rate does not exceed 2°C / min; D. Release the pressure, cool down and open the autoclave.

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