阅读说明：本技术 一种抗烧蚀轻质承载u型罩体及其制备方法 (Ablation-resistant light-weight bearing U-shaped cover body and preparation method thereof ) 是由 许晓洲 柯红军 谢永旺 汪东 尹先鹏 李娜 王国勇 李丽英 张昊 于 2021-06-15 设计创作，主要内容包括：本发明提出一种抗烧蚀轻质承载U型罩体及其制备方法。U型罩体最外面为热防护抗烧蚀层,最里面为结构承载层,结构承载层还可设置具有一定宽度和高度的加强筋条增加承载能力,热防护层和结构承载层之间采用耐高温硅橡胶进行粘接。本发明采用热防护抗烧蚀层与结构承载层相互配合的方法,热防护层采用耐烧蚀纤维增强酚醛树脂体系,结构承载层采用碳纤维增强树脂基体系,承载层与热防护层相互配合可以在结构减重的基础上实现U型罩体的耐烧蚀性能和力学性能的平衡。(The invention provides an anti-ablation light-weight bearing U-shaped cover body and a preparation method thereof. The outermost of U type cover body is thermal protection anti-ablation layer, and the innermost is the structure bearing layer, and the structure bearing layer still can set up the strengthening rib strip that has certain width and height and increase bearing capacity, adopts high temperature resistant silicon rubber to bond between thermal protection layer and the structure bearing layer. The invention adopts a method that the thermal protection ablation-resistant layer is matched with the structural bearing layer, the thermal protection layer adopts an ablation-resistant fiber reinforced phenolic resin system, the structural bearing layer adopts a carbon fiber reinforced resin matrix system, and the bearing layer and the thermal protection layer are matched with each other, so that the balance of the ablation resistance and the mechanical property of the U-shaped cover body can be realized on the basis of structure weight reduction.)

1. The ablation-resistant light-weight bearing U-shaped cover body is characterized by comprising an outermost thermal protection ablation-resistant layer, an innermost structural bearing layer and a middle high-temperature-resistant bonding layer, wherein the thermal protection ablation-resistant layer is an ablation-resistant fiber reinforced phenolic resin layer, and the structural bearing layer is a carbon fiber reinforced resin matrix composite material.

2. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1, wherein: the total thickness of the thermal protection ablation-resistant layer is 5-20 mm, the thickness of the structure bearing layer is 1-8 mm, and the thickness of the thermal protection ablation-resistant layer and the thickness of the structure bearing layer are selected according to the requirements of actual working conditions.

3. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1, wherein: the resin matrix selected by the structural bearing layer is high-temperature-resistant structural resin, and the temperature-resistant grade of the structural bearing layer is determined according to the use working condition; the high-temperature-resistant structural resin is epoxy resin, bismaleimide resin or polyimide.

4. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1, wherein: the heat protection anti-ablation layer is made of phenolic resin, the temperature resistance level of the phenolic resin is determined according to the working condition of use, and the phenolic resin is one or more of barium phenolic aldehyde, boron phenolic aldehyde and molybdenum phenolic aldehyde.

5. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1 or 2, wherein: the ablation-resistant fiber adopted by the thermal protection ablation-resistant layer is one of glass fiber, high silica fiber and aramid fiber.

6. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1, wherein: the high-temperature-resistant adhesive layer is a high-temperature-resistant silicon rubber adhesive layer.

7. The ablation-resistant lightweight load-bearing U-shaped shield of claim 1, wherein: the structural bearing layer contains reinforcing ribs to enhance the bearing capacity and the deformation resistance.

8. A preparation method of an anti-ablation light-weight bearing U-shaped cover body is characterized by comprising the following steps:

step one, preparing a structural bearing layer with reinforcing ribs: selecting high-temperature-resistant resin according to corresponding working condition application requirements, and preparing a carbon fiber prepreg by a hot melting method or a wet process to obtain a corresponding resin-based carbon fiber prepreg; cutting resin-based carbon fiber prepreg according to the structural size of a structural bearing layer with reinforcing ribs to obtain large-area skin rectangular prepreg and broken skin rectangular prepreg, firstly laying the broken skin prepreg on a U-shaped metal male die, then adding unidirectional reinforcing rib prepreg, then laying large-area skin, and then carrying out autoclave curing and demoulding to obtain the structural bearing layer with reinforcing ribs;

step two, preparing a thermal protection ablation-resistant layer: preparing ablation-resistant fiber prepreg from phenolic resin by a hot melting method; paving an ablation-resistant fiber prepreg on a U-shaped metal female die according to the structural size of a U-shaped cover body, and then performing autoclave curing and demolding to obtain a thermal protection ablation-resistant layer; or winding the ablation-resistant fiber prepreg into a blank by an oblique overlapping winding process, and then transferring the blank to a U-shaped metal female die for curing to obtain a thermal protection ablation-resistant layer;

thirdly, processing, perforating, trimming and polishing the structural bearing layer with the reinforcing ribs and the thermal protection ablation resistant layer obtained in the first step and the second step according to the size of the ablation resistant light-weight bearing U-shaped cover body to obtain a structural bearing layer and a thermal protection ablation resistant layer which can be used for bonding;

and fourthly, bonding the structural bearing layer which can be bonded and is obtained in the third step with the thermal protection ablation-resistant layer by adopting a high-temperature-resistant bonding agent to obtain the ablation-resistant light-weight bearing U-shaped cover body.

9. The method for preparing an ablation-resistant lightweight load-bearing U-shaped cover according to claim 8, characterized in that: the carbon fiber in the carbon fiber prepreg adopted by the structural bearing layer is T300-grade, T700-grade or T1000-grade unidirectional fiber, the structural bearing layer is adjusted according to the structural design requirement of the U-shaped cover body structural bearing layer, and the thickness of each layer is 0.1-1.4 mm.

10. The method for preparing an ablation-resistant lightweight load-bearing U-shaped cover according to claim 8, characterized in that: the high-temperature resistant adhesive layer has a temperature resistant grade of more than 200 ℃ and a thickness of 0.1-1 mm.

Technical Field

The invention relates to an ablation-resistant light-weight bearing U-shaped cover body and a preparation method thereof, belonging to the technical field of ablation-resistant composite materials.

Background

With the development of aerospace technology, the requirements of high flight speed, long range and high effective load are put forward on an aircraft. As aircraft flight speed increases, there is intense aerodynamic heating of the aircraft surface, resulting in an increase in surface stagnation temperature. And as the airspeed increases, the stagnation temperature increases in positive correlation with the mach number square of the airspeed.

The traditional aircraft engine fairing is mainly made of metal materials, an anti-ablation coating is added on the surface of the metal materials, the ablation coating is used for preventing heat, and the metal layer provides load bearing to realize cooperation. However, the metal material has a high density, which is not favorable for the requirements of high flight speed, long range and high payload, and the traditional structural resin-based composite material is generally difficult to be directly exposed to more than 500 ℃ for use. Therefore, the development of aircraft shields has been limited.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an anti-ablation light-weight bearing U-shaped cover body and a preparation method thereof.

The technical solution of the invention is as follows:

an ablation-resistant light-weight bearing U-shaped cover body comprises an outermost thermal protection ablation-resistant layer, an innermost structural bearing layer and a middle high-temperature-resistant bonding layer, wherein the thermal protection ablation-resistant layer is an ablation-resistant fiber reinforced phenolic resin layer, and the structural bearing layer is a carbon fiber reinforced resin matrix composite material.

Furthermore, the ablation-resistant fiber adopted by the thermal protection ablation-resistant layer is a non-combustible fiber and has heat-insulating property; the ablation-resistant fiber is a fiber with ablation resistance commonly used in the field, such as glass fiber, high silica fiber, aramid fiber and the like.

Furthermore, the resin substrate selected for the structural bearing layer is not limited by special types, the temperature resistance level of the structural bearing layer is determined according to the working condition, and high-temperature resistant structural resins such as epoxy resin, bismaleimide resin or polyimide can be selected; the high temperature resistant adhesive requires a heat resistance level of 200 ℃ or higher.

Further, the thickness of the thermal protection ablation-resistant layer is 5-20 mm, the greater the thickness is, the better the ablation-resistant performance is, but the greater the weight is, the total thickness is too high, and the effective load of the aircraft can be influenced; the thickness of the structure bearing layer is 1-8 mm, the larger the thickness is, the better the mechanical property is, but the larger the weight is, the total thickness is too high, and the effective load of the aircraft can be influenced. The thickness of the thermal ablation resistant layer and the structural support layer are selected by those skilled in the art based on the specific ablation performance and structural support performance requirements.

Furthermore, the phenolic resin adopted by the thermal protection ablation-resistant layer is not limited by a special type, the temperature-resistant grade of the thermal protection ablation-resistant layer is determined according to the temperature of the use working condition, and one or more of barium phenolic aldehyde, boron phenolic aldehyde, molybdenum phenolic aldehyde and the like can be selected.

Further, the high-temperature-resistant adhesive layer is preferably a high-temperature-resistant silicone rubber adhesive layer.

Further, the structural bearing layer contains reinforcing ribs to enhance the bearing capacity and the deformation resistance.

A preparation method of an anti-ablation light-weight bearing U-shaped cover body is realized by the following steps:

firstly, preparing a U-shaped cover body with a reinforcing rib structure bearing layer:

a1.1, selecting high-temperature resistant resins such as epoxy resin, bismaleimide resin or polyimide and the like according to corresponding working condition application requirements, and then preparing a carbon fiber prepreg by a hot melting method or a wet process to obtain a corresponding resin-based carbon fiber prepreg;

a1.2, cutting the resin-based carbon fiber prepreg obtained in the step A1.1 according to the structural size of a bearing layer with a reinforcing rib structure to obtain a large-area skin rectangular prepreg and a divided skin rectangular prepreg, firstly laying the divided skin prepreg on a U-shaped metal male die (an area which is provided with a recess and can be used for placing reinforcing ribs on the metal male die), then adding a unidirectional reinforcing rib prepreg, laying a large-area skin, and then carrying out autoclave curing and demoulding to obtain the bearing layer with the reinforcing rib structure; the curing process depends on the type of resin matrix employed.

Step two, preparing a thermal protection ablation-resistant layer:

a2.1, preparing ablation-resistant fiber prepreg from phenolic resin by a hot melting method;

a2.2, laying the ablation-resistant fiber prepreg obtained from the A2.1 on a U-shaped metal female die according to the structural size of a U-shaped cover body, then carrying out autoclave curing and demolding to obtain a thermal protection ablation-resistant layer, wherein the thermal protection ablation-resistant layer can also wind the ablation-resistant fiber prepreg obtained from the A2.1 into a blank by an oblique overlapping winding process, and then transferring the blank to the U-shaped metal female die for curing;

thirdly, processing, perforating, trimming and polishing the structural bearing layer with the reinforcing ribs and the thermal protection ablation resistant layer obtained in the first step and the second step according to the size of the ablation resistant light-weight bearing U-shaped cover body to obtain a structural bearing layer and a thermal protection ablation resistant layer which can be used for bonding;

and fourthly, bonding the structural bearing layer which can be bonded and is obtained in the third step with the thermal protection ablation-resistant layer by adopting a high-temperature-resistant bonding agent to obtain the ablation-resistant light-weight bearing U-shaped cover body.

The preparation of resin prepregs such as epoxy resin, bismaleimide resin, polyimide and the like and phenolic resin fiber prepregs or the hot-melt method and the wet process of prepregs is a well-known technique in the art, and is not described herein in detail.

The carbon fibers in the high-temperature-resistant resin-based carbon fiber prepreg adopted by the invention can be T300-grade, T700-grade or T1000-grade unidirectional fibers or fiber cloth, and are adjusted according to the requirements of a U-shaped cover body, the thickness of each layer is 0.1-1.4 mm, the thickness of the unidirectional prepreg is preferably 0.125mm, and the thickness of the fiber cloth is preferably 0.2 mm.

The thickness of each layer of the ablation-resistant fiber prepreg adopted by the invention is 0.1-0.4 mm, and preferably 0.2 mm.

The high-temperature-resistant adhesive adopted by the invention has the temperature resistance grade of more than 200 ℃, can be usually RTV-2, RTV-400 or other adhesives with good heat resistance and adhesive property, and has the thickness of 0.1-1 mm, preferably 0.3 mm.

Compared with the prior art, the invention has the beneficial effects that:

(1) the U-shaped cover body adopts a light composite structure with different functional layer structures, and the weight is lower than that of a metal material. The thermal protection ablation-resistant layer is matched with the structural bearing layer, and the balance of the ablation-resistant performance and the mechanical property of the U-shaped cover body can be realized on the basis of weight reduction of the structure.

(2) The U-shaped cover body is made of composite materials, the thicknesses and materials of the heat-proof layer and the bearing layer can be adjusted according to needs, and each functional layer can better play respective role and has strong designability.

Drawings

FIG. 1 is a schematic structural view of a U-shaped housing; wherein: 1-structural bearing layer, 2-high temperature resistant adhesive layer, 3-thermal protection anti-ablation layer and 4-reinforcing ribs.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples, but the present invention is not limited to the following examples.

The invention is shown in figure 1, which is composed of a heat protection anti-ablation layer as an outermost layer and a structure bearing layer as an inner layer, wherein the two layers are bonded by adopting a high-temperature resistant adhesive. Wherein the heat protection ablation-resistant layer is made of ablation-resistant fiber phenolic resin material, wherein the ablation-resistant fiber is a non-combustible fiber and has heat-insulating property; the resin matrix selected for the structure bearing layer is not limited by special types, the temperature resistance level of the structure bearing layer is determined according to the working condition of use, and high-temperature resistant structural resins such as epoxy resin, bismaleimide resin or polyimide can be selected; the high temperature resistant adhesive requires a heat resistance level of 200 ℃ or higher.

Example 1:

an anti-ablation light-weight bearing U-shaped cover body structure:

the thickness of the outer thermal protection ablation-resistant layer is 15mm, and the thermal protection ablation-resistant layer is made of glass fiber cloth reinforced phenolic resin; the structural bearing layer adopts 1mm of T1000 carbon fiber reinforced bismaleimide resin; the total thickness of the U-shaped cover body is 15.3 mm.

Step one, preparing a structural bearing layer with reinforcing ribs on the U-shaped cover body:

a1.1, preparing a T1000 carbon fiber unidirectional prepreg by using bismaleimide resin through a hot melting process to obtain a corresponding T1000/bismaleimide resin prepreg;

a1.2, cutting the T1000/bismaleimide resin prepreg obtained from the A1.1 according to the structural size of a U-shaped cover body reinforcing rib structure bearing layer to obtain a large-area skin rectangular prepreg and a cut skin rectangular prepreg, laying the cut skin rectangular prepreg on a U-shaped metal male die, adding a unidirectional reinforcing rib prepreg, laying a large-area skin, and then carrying out autoclave curing and demolding to obtain the U-shaped cover body reinforcing rib structure bearing layer, wherein the large-area skin is uniformly and symmetrically laid according to an angle of [45/0/-45/90/90/-45/0/45 ];

the modified bismaleimide resin is cured at 100 ℃ for 1 hour, then cured under pressure at 160 ℃ for 2 hours, finally cured at 250 ℃ for 4 hours, and cooled and demoulded to obtain the structural bearing layer with the U-shaped cover body provided with the reinforcing ribs.

Step two, preparing a thermal protection ablation-resistant layer:

a2.1, preparing an ablation-resistant glass fiber cloth prepreg by using phenolic resin through a hot melting method to obtain an ablation-resistant glass fiber cloth prepreg;

a2.2, cutting the ablation-resistant glass fiber cloth prepreg obtained in the A2.1 according to the structural size of a U-shaped cover body to obtain the prepreg, laying to obtain a prepreg laying part of about 15mm, and then carrying out autoclave curing and demolding to obtain a thermal protection ablation-resistant layer;

the phenolic resin curing process comprises the steps of preserving heat for 1h at 90 ℃, and then carrying out pressure curing for 2h at 130 ℃ to cure the whole structure.

And thirdly, processing, perforating, trimming and polishing the structural bearing layer and the thermal protection ablation resistant layer obtained in the first step and the second step according to the structural size of the U-shaped cover body to obtain the structural bearing layer and the thermal protection ablation resistant layer which can be used for bonding.

And fourthly, bonding the structural bearing layer which can be bonded and is obtained in the third step with the thermal protection ablation-resistant layer by adopting high-temperature-resistant silicon rubber RTV-2 to obtain an ablation-resistant light-weight bearing U-shaped cover body structure.

In the embodiment, through a quartz lamp radiation heating experiment test, when the temperature of the outer heat-proof layer is 700 ℃, the temperature of the bearing layer of the innermost layer structure is 83 ℃, and the debonding phenomenon does not occur.

Example 2:

an anti-ablation light-weight bearing U-shaped cover body structure:

the thickness of the outer thermal protection ablation-resistant layer is 5mm, and the thermal protection ablation-resistant layer is made of high silica fiber cloth reinforced phenolic resin; the structural bearing layer is made of 8mm T700 carbon fiber reinforced polyimide resin; the total thickness of the U-shaped cover body is 13.3 mm.

Firstly, preparing a structural bearing layer of a U-shaped cover body with reinforcing ribs,

a1.1, preparing a T700 carbon fiber unidirectional prepreg by polyimide resin through a wet process to obtain a corresponding T700/polyimide resin prepreg;

a1.2, cutting the T700/polyimide resin prepreg obtained from A1.1 according to the structural size of a structural bearing layer with U-shaped cover body reinforcing ribs to obtain a large-area skin rectangular prepreg and a cut skin rectangular prepreg, laying the cut skin rectangular prepreg on a U-shaped metal male die, adding a unidirectional reinforcing rib prepreg, laying a large-area skin, and then carrying out autoclave curing and demolding to obtain the U-shaped cover body structural bearing layer with the reinforcing ribs, wherein the large-area skin is laid according to the structural size of [45/0/-45/90 ]]_8SSpreading layers symmetrically and evenly in angle;

the polyimide resin is cured at 200 ℃ for 3 hours, then pressurized at 310-350 ℃, heated to 380 ℃ for curing for 3 hours, and cooled and demoulded to obtain the structural bearing layer with the U-shaped cover body and the reinforcing ribs.

Step two, preparing a thermal protection ablation-resistant layer:

a2.1, preparing a high-silica fiber cloth prepreg by using phenolic resin through a hot melting method to obtain an ablation-resistant fiber cloth prepreg;

a2.2, cutting the high silica fiber cloth prepreg obtained from the A2.2 according to the structural size of a U-shaped cover body to obtain the prepreg, laying to obtain a prepreg laying part of about 5mm, and then curing and demolding by an autoclave to obtain a thermal protection ablation-resistant layer;

the phenolic resin curing process comprises the steps of preserving heat for 1 hour at 90 ℃, and then carrying out pressure curing for 2 hours at 130 ℃ to cure the whole structure.

And thirdly, processing, perforating, trimming and polishing the structural bearing layer and the thermal protection ablation resistant layer obtained in the first step and the second step according to the structural size of the U-shaped cover body to obtain the structural bearing layer and the thermal protection ablation resistant layer which can be used for bonding.

And fourthly, bonding the structural bearing layer which can be bonded and is obtained in the third step with the thermal protection ablation-resistant layer by adopting high-temperature-resistant silicon rubber RTV-400 to obtain an ablation-resistant light-weight bearing U-shaped cover body structure.

In the embodiment, through a quartz lamp radiation heating experiment test, when the temperature of the outer heat-proof layer is 700 ℃, the temperature of the bearing layer of the innermost layer structure is 203 ℃, and the debonding phenomenon does not occur.

Example 3:

an anti-ablation light-weight bearing U-shaped cover body structure:

the thickness of the outer thermal protection ablation-resistant layer is 20mm, and the thermal protection ablation-resistant layer adopts high silica fiber cloth reinforced phenolic resin; the structural bearing layer is made of 3mm T300 carbon fiber reinforced epoxy resin; the total thickness of the U-shaped cover body is 23.3 mm.

Step one, preparing a structural bearing layer with reinforcing ribs on the U-shaped cover body:

a1.1, preparing a T700 carbon fiber unidirectional prepreg by epoxy resin through a hot-melt process to obtain a corresponding T700/epoxy resin prepreg;

a1.2, cutting the T700/epoxy resin prepreg obtained from the A1.1 according to the structural size of a structural bearing layer with reinforcing ribs of a U-shaped cover body to obtain a large-area rectangular skin prepreg and a cut rectangular skin prepreg, laying the cut rectangular skin prepreg on a U-shaped metal male die, adding a unidirectional reinforcing rib prepreg, laying a large-area skin, carrying out autoclave curing and demolding to obtain the structural bearing layer with the reinforcing ribs of the U-shaped cover body, wherein the large-area skin is laid according to the structural size of [45/0/-45/90 ]]_3SAngle of rotationBalanced and symmetrical layering;

and the epoxy resin curing process comprises the steps of preserving heat at 90 ℃ for 30 minutes, heating to 110 ℃ for pressurizing, heating to 130 ℃ for curing for 2 hours, cooling and demolding to obtain the structural bearing layer with the U-shaped cover body and the reinforcing ribs.

Secondly, preparing a thermal protection anti-ablation layer,

a2.1, preparing a high-silica fiber cloth prepreg by using phenolic resin through a hot melting method to obtain an ablation-resistant fiber cloth prepreg;

a2.2, cutting the high silica fiber cloth prepreg obtained in the step A2.1 according to the structural size of a U-shaped cover body to obtain the prepreg, laying to obtain a prepreg laying part of about 20mm, and then curing and demolding in an autoclave to obtain a thermal protection ablation-resistant layer;

the phenolic resin curing process comprises the steps of preserving heat for 1 hour at 90 ℃, and then carrying out pressure curing for 2 hours at 130 ℃ to cure the whole structure.

And thirdly, processing, perforating, trimming and polishing the structural bearing layer and the thermal protection ablation resistant layer obtained in the first step and the second step according to the structural size of the U-shaped cover body to obtain the structural bearing layer and the thermal protection ablation resistant layer which can be used for bonding.

And fourthly, bonding the structural bearing layer capable of being bonded and the thermal protection ablation-resistant layer obtained in the third step by adopting high-temperature-resistant silicon rubber RTV-2 to obtain an ablation-resistant light-weight bearing U-shaped cover body structure.

In the embodiment, through a quartz lamp radiation heating experiment test, when the temperature of the outer heat-proof layer is 700 ℃, the temperature of the bearing layer of the innermost layer structure is 52 ℃, and the debonding phenomenon does not occur.

The invention has not been described in detail and is in part known to those of skill in the art.

The particular embodiments of the present invention disclosed above are illustrative only and are not intended to be limiting, since various alternatives, modifications, and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The invention should not be limited to the disclosure of the embodiments in the present specification, but the scope of the invention is defined by the appended claims.