CN115583052A

CN115583052A - Forming method of composite material cylindrical part

Info

Publication number: CN115583052A
Application number: CN202211214187.6A
Authority: CN
Inventors: 周耀忠; 曹宇; 侯敏; 徐蒙蒙
Original assignee: Beijing Xinghang Electromechanical Equipment Co Ltd
Current assignee: Beijing Xinghang Electromechanical Equipment Co Ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2023-01-10

Abstract

The invention relates to the technical field of non-metal composite material manufacturing, in particular to a method for forming a composite material cylindrical part, which comprises the following steps: dipping and molding the heat-proof layer; laying a first transition buffer structure; vacuum leading-in forming of the inner side wall plate; forming an axial support structure; assembling the inner side wall plate and the axial support structure; the radial filling structure and the radial supporting structure are fixed; laying a second transition buffer structure; and forming the outer side wall plate. When the heat-proof layer and the inner and outer side wall plates are processed, a vacuum impregnation or vacuum leading-in process is adopted, and the axial support structure and the radial support structure are arranged on the inner side of the outer wall of the cylindrical part, so that stress balance is facilitated, and the probability of damage of the cylindrical part due to external force is reduced; the shear strength of the composite material with different expansion rates is improved by arranging the transition buffer structure, so that the damage caused by different thermal expansion rates is reduced, and the service life is prolonged; when in process forming, the problem of glue accumulation at the round angle is solved by processing the connecting round angle.

Description

Forming method of composite material cylindrical part

Technical Field

The invention relates to the technical field of non-metal composite material manufacturing, in particular to a method for forming a composite material cylindrical part.

Background

The cylindrical part is often used as a launching component of a launching tube of fireworks and civil shooting equipment, and the launching component of the launching tube not only needs to meet the structural and functional requirements, but also needs to meet the requirements of high strength, light weight and portability at high temperature. The metal structure barrel in the traditional technology has the problems of heavy weight, welding deformation, easy corrosion and the like, and the existing composite material launching barrel has the problems of poor rigidity, heavy weight, large volume, poor heat insulation capability, easy cracking of different interlayer materials, short service life, incapability of being repeatedly utilized and difficulty in heat insulation and volume.

Therefore, there is an urgent need to develop a portable emitter tube having good mechanical strength at high temperature, good heat-insulating property, and long service life.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a method for forming a composite material tubular part, so as to solve at least one of the technical problems of low high-temperature mechanical strength, poor heat insulation performance and short service life of the existing tubular part such as an emitting part in an emitting tube.

The invention is mainly realized by the following technical scheme:

in one aspect, the invention provides a method for forming a composite material cylindrical part, which comprises the following steps:

step 1, dip forming of the thermal insulation layer:

preparing a heat-proof and insulating layer in a mould by adopting a vacuum impregnation process;

step 2, laying a first transition buffer structure:

laying each layer of raw materials of the first transition buffer structure layer by taking the outer surface of the heat-proof layer as a datum plane; the first transition buffer structure (8) is a multi-layer composite structure comprising a tough support layer, and comprises a first rigid connection layer (801), a first tough support layer (802) and a second rigid connection layer (803) which are sequentially distributed from a high-temperature area to a low-temperature area; the tough supporting layer can be matched with a heat insulation layer (1) and an inner side wall plate (3) with different thermal expansion coefficients;

step 3, vacuum introduction and forming of the inner side wall plate:

preparing a cylindrical part preform with an inner side wall plate fixed outside by taking the outer surface of the first transition buffer structure as a reference surface and adopting a vacuum introduction process;

step 4, forming an axial supporting structure:

preparing an axial supporting structure in the die by adopting an autoclave process;

step 5, assembling the inner side wall plate and the axial support structure:

fixedly connecting an axial supporting structure at a preset position of the inner side wall plate to obtain a cylindrical part prefabricated body covered with the axial supporting structure;

step 6, fixing the radial filling structure and the radial supporting structure:

bonding and fixing a radial filling structure on the outer wall of the cylindrical part prefabricated body covered with the axial support structure; bonding and fixing a radial supporting structure on the outer wall of the radial filling structure, and curing and molding under vacuum to obtain a cylindrical part prefabricated body with the radial filling structure and the radial supporting structure;

step 7, laying a second transition buffer structure:

laying a second transition buffer structure on the outer wall of the cylindrical part prefabricated body with the radial filling structure;

step 8, forming of an outer side wall plate:

and preparing an outer side wall plate on the outer wall of the second transition buffer structure by adopting a vacuum introduction process.

Preferably, in step 8, in order to prepare the outer sidewall plate by using the vacuum import process, a release fabric, an isolation film, a flow guide net and a vacuum bag are sequentially laid on the outer wall of the second transition buffer structure.

Preferably, conformal rubber is placed between the vacuum bag and the flow guide net at a fillet at the joint of the outer side wall plate and the fixed end of the radial support structure; and two independent demoulding cloths are needed to be lapped and adhered at the fillet, and two independent diversion nets are needed to be lapped and adhered at the fillet.

Preferably, in the step 1, the vacuum degree is more than or equal to 980mbar, the heating temperature is 80-180 ℃, and the forming time is 12-24 hours.

Preferably, the step 3 comprises the following steps:

step 3.1: preheating the prefabricated body of the inner side wall plate at 120-130 ℃ after vacuumizing, and gradually increasing within the range of 600-980 mbar after the negative pressure pumping operation is started;

step 3.2: preheating resin at 100-120 deg.c and introducing the resin into the preheated prefabricated inner wall board;

step 3.3: and carrying out heat treatment molding on the inner side wall plate preform subjected to resin introduction at 130-150 ℃ and 170-180 ℃ in sequence.

Preferably, the step 4 comprises the following steps:

step 4.1: pouring a panel of an external reinforced structure in a mould by using fiber prepreg, and carrying out vacuum compaction for 1 time by paving 3-5 layers of the fiber prepreg for 15-50 min, wherein the vacuum pressure is 600-980 mbar;

step 4.2: laying fiber prepreg layer by layer to prepare reinforcing ribs at the position where the internal filling structure is positioned on the panel, and performing pre-compaction treatment in a hot compaction mode at the compaction temperature of 130-140 ℃ for 15-50 min;

step 4.3: the prefabricated body with the reinforcing ribs 2032 is placed in a vacuum bag in a hot-pressing tank, and is subjected to heat treatment and molding in two stages at 130-150 ℃ and 170-180 ℃ sequentially under the pressure of 0.4-0.6 MPa.

Preferably, the step 5 comprises the following steps: the axial supporting structure is tightly connected with a cylindrical part prefabricated body of which the outer part is fixed with an inner side wall plate through an adhesive film, and the cylindrical part prefabricated body is subjected to heat treatment forming at two stages of 130-150 ℃ and 170-180 ℃ in sequence under the negative pressure environment with gradually increasing range of 600-980 mbar.

Preferably, the step 6 comprises the following steps:

step 6.1: fixing a radial filling structure on the outer wall of an inner side wall plate of the cylindrical part prefabricated body covered with the axial supporting structure, and positioning and fixedly connecting the radial filling structure on the outer wall of the radial filling structure;

step 6.2: the cylindrical part preform with the radial filling structure and the radial supporting structure is subjected to heat treatment molding at 130-150 ℃ and 170-180 ℃ in sequence under the negative pressure environment with gradually increasing range of 600-980 mbar. On the other hand, the invention provides a composite material cylindrical part which comprises an anti-heat-insulation layer, a first transition buffer structure, an inner side wall plate, a radial filling structure and an outer side wall plate which are sequentially arranged from inside to outside;

the first transition buffer structure is a multilayer composite structure comprising a tough supporting layer, and the tough supporting layer can be matched with an anti-heat-insulation layer and an inner side wall plate which have different thermal expansion coefficients.

Preferably, the thermal expansion coefficient difference between the thermal insulation layer and the inner side wall plate is 8 x 10 ^-6 m/℃～9×10 ^-6 m/℃。

Preferably, the first transition buffer structure comprises a first rigid connection layer, a first flexible support layer and a second rigid connection layer which are sequentially distributed from a high-temperature area to a low-temperature area.

Preferably, the first rigid connection layer is a glass fiber felt layer, the first flexible support layer is a glass fiber cloth layer, and the second rigid connection layer is a glass fiber felt layer.

Preferably, the glass fiber felt layer of the first rigid connecting layer is 2-3A layer of a material selected from the group consisting of,the glass fiber cloth layer of the first tough supporting layer is 1-3 layers, and the glass fiber felt layer of the second rigid connecting layer is 2-3 layersLayer(s)。

Preferably, the glass fiber mats of the first rigid connecting layer and the second rigid connecting layer have the fiber length of 2-10 mm; the glass fiber mat is chopped strands; the glass fiber cloth is as follows: any one of a grain cloth, an twill cloth and a plain cloth; the density of the glass fiber cloth is 170g/cm ³ ～220g/cm ³ Twill cloth.

Preferably, the cylindrical part is further provided with an axial supporting structure which is axially parallel to the cylindrical part, and the axial supporting structure is arranged in the radial filling structure and fixed on the outer wall of the inner side wall plate.

Preferably, the axial support structures are multiple and are distributed at intervals along the circumferential direction of the cylindrical part.

Preferably, the axial support structure includes an inner inflatable structure and an outer inflatable structure surrounding the inner inflatable structureA section reinforcement structure; the external reinforcing structure comprises a panel fixedly connected with the inner side wall plate and a reinforcing rib surrounding and fixing the internal fillable structure。

Preferably, the face plate and the reinforcing rib are of a fiber reinforced resin matrix structure.

Preferably, the fiber reinforced structural layer in the axial support structure is quasi-isotropic; the reinforced fiber of the fiber reinforced structural layer is one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber.

Preferably, the reinforcing fibers of the fiber reinforced resin matrix structure are carbon fibers.

Preferably, the matrix resin of the fiber reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin and epoxy resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin and epoxy resin; the internal fillable structure is a lightweight material with a hollow micropore or bubble structure.

Preferably, the inner fillable structure is any one of PEI foam or PMI foam; the matrix resin of the fiber reinforced resin matrix structure is EH301 epoxy resin.

Preferably, the cylindrical part is further provided with a radial support structure, and the radial support structure is arranged between the radial filling structure and the outer side wall plate.

Preferably, the radial support structures are arranged at intervals along the axial direction of the cylindrical part.

Preferably, the radial support structure is a lightweight material of hollow microporous or bubble structure.

Preferably, the radial support structure is any one of PEI foam or PMI foam.

Preferably, a second transition buffer structure is further arranged among the radial support structure, the radial filling structure and the outer side wall plate; the second transition buffer structure is a multi-layer composite structure including a ductile backing layer capable of mating the radial support structure and the outer sidewall plate having different coefficients of thermal expansion, and the ductile backing layer capable of mating the radial fill structure and the outer sidewall plate having different coefficients of thermal expansion.

Preferably, the difference between the thermal expansion coefficients of the radial support structure or the radial filling structure and the outer side wall plate is 35 × 10 ^-6 m/℃～41×10 ^-6 m/℃。

Preferably, the second transition buffer structure comprises a third rigid connection layer, a second flexible support layer and a fourth rigid connection layer which are sequentially distributed from the high-temperature area to the low-temperature area.

Preferably, the third rigid connection layer is a glass fiber felt layer, the second flexible support layer is a glass fiber cloth layer, and the fourth rigid connection layer is a glass fiber felt layer.

Preferably, the glass fiber felt layer of the third rigid connecting layer is 2-3A layer of a polymer,the glass fiber cloth layer of the second tough supporting layer is 1-3 layers, and the glass fiber felt layer of the fourth rigid connecting layer is 2-3 layersLayer(s)。

Preferably, the fiber length of the glass fiber mats of the third rigid connecting layer and the fourth rigid connecting layer is 10-15 mm; the glass fiber mat is chopped strands; the glass fiber cloth is as follows: any one of a grain cloth, an twill cloth and a plain cloth; the density of the glass fiber cloth is 170g/cm ³ ～220g/cm ³ Twill cloth.

Preferably, the thermal insulation prevention layer adopts a fiber reinforced resin matrix structure.

Preferably, the matrix resin of the fiber reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin and arylacetylene resin.

Preferably, the matrix resin of the fiber reinforced resin matrix structure is an interpenetrating phase composite modified phenolic resin.

Preferably, the fiber reinforced resin matrix structure is provided with a fiber reinforced structural layer.

Preferably, the fiber reinforced structure layer adopts one or more of fiber woven structure layer, fiber cloth laminated paving layer, chopped strand mat needling layer and fabric laminated needling layer.

Preferably, the reinforcing fiber of the fiber reinforced structure layer is one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber.

Preferably, the reinforcing fibers of the fiber reinforced resin matrix structure are quartz fibers, carbon fibers or a mixture of both.

Preferably, the inner side wall plate and the outer side wall plate are fiber reinforced resin matrix structures, and the fiber reinforced resin matrix structures are provided with fiber reinforced structure layers.

Preferably, the matrix resin of the fiber reinforced resin matrix structure is one or more of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin and epoxy resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin and epoxy resin.

Preferably, the matrix resin of the fiber reinforced resin matrix structure is EH301 epoxy resin.

Preferably, the radial filling structure is a lightweight material with a hollow micropore or bubble structure.

Preferably, the radial filling structure is any one of PEI foam or PMI foam.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

(1) Compared with the prior art that the shear strength of the inner side wall is improved to 60MPa from 55MPa, and the shear strength of the outer side wall is improved to 70MPa from 60MPa, the shear strength is respectively improved by 9.09% and 16.6%.

(2) The transition buffer structure can adopt a structural form of glass fiber mat, glass fiber cloth and glass fiber mat, wherein the glass fiber cloth layer can generate certain creep deformation when being subjected to external force, the flexible structure greatly improves the stress difference and cracking caused by different thermal expansion coefficients of different materials when the temperature changes, and a good stress buffer layer is integrally formed; the transition buffer structure can be arranged at the joint of the radial support structure and the outer side wall plate, and the radial support structure is tightly and fixedly connected with the glass fiber felt which is tightly adjacent to the outer side wall plate, so that the defects of weak strength and poor shearing resistance of the glass fiber cloth body can be effectively avoided; and then effectively cushion because of stress and deformation that the material thermal expansion rate difference brought that inside and outside temperature difference arouses in the inside wall board, and then can effectively avoid the chap and the deformation of the inside and outside of inside wall board, improved life greatly.

(3) When the outer side wall plate is formed, the flow guide net at the connecting fillet of the radial filling structure and the radial supporting structure can be subjected to lap joint treatment, and the conformal rubber is placed between the fillet and the vacuum bag, so that the defects that the vacuum bag is difficult to attach to the connecting fillet and the pressure is low and the rubber is not completely discharged in the traditional process can be overcome, and the problem of rubber accumulation at the fillet is solved.

(4) The axial supporting structure and the radial supporting structures are distributed along the circumferential direction, and the interiors of the axial supporting structure and the radial supporting structures are subjected to weight reduction treatment, so that the structure strength is improved, the additional weight brought by the supporting structures is greatly reduced, and the cylindrical part has the advantage of light weight; meanwhile, when the heat-insulating layer and the inner and outer side wall plates are processed, a vacuum impregnation or vacuum introduction process is adopted, the axial supporting structure and the radial supporting structure can be arranged on the inner side of the outer wall of the cylindrical part, the integral appearance is realized, and meanwhile, the structure is beneficial to external force dispersion and more balanced stress when being subjected to external force, so that the probability of damage of the cylindrical part due to the external force can be reduced.

(5) According to the invention, the axial support structure, the radial support structure and the radial filling structure can adopt high-temperature-resistant PEI or PMI high-temperature-resistant sponge, so that the lightweight heat insulation is realized, and the PEI or PMI high-temperature-resistant sponge still has good strength even at high temperature.

(6) The heat-insulating layer can adopt an interpenetrating phase composite material (IPC), the surface can be ceramic and hard at high temperature, and the heat-insulating layer has a uniform nano-pore structure and good heat-insulating property; compared with the high-temperature resistant resin in the prior art, the heat insulation performance is greatly improved, and the heat conductivity is reduced to 0.066W/(mK) from 0.078W/(mK) by 15.4%.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a schematic cross-sectional view of a composite tubular article according to one embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a state where no glue deposits are formed at a connecting corner between an outer sidewall plate and a radial support structure according to an embodiment of the present invention;

FIG. 3 is a schematic view illustrating a state of glue deposition at a connection corner between an outer sidewall plate and a radial support structure according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a process arrangement for vacuum impregnation and vacuum introduction in one embodiment of the present invention;

FIG. 5 is a schematic view of the internal structure of an axial support structure according to an embodiment of the present invention;

FIG. 6 is a schematic representation of the lay-up of layers of carbon fiber fabric prepreg in one embodiment of the present invention;

FIG. 7 is a schematic diagram of a first transition buffer structure according to an embodiment of the present invention;

FIG. 8 is a side view of a composite tubular article according to one embodiment of the present invention;

FIG. 9a is a sectional view taken along line A1-A1 of FIG. 8;

FIG. 9b is a sectional view taken along the line A2-A2 of FIG. 8;

FIG. 10a is a sectional view of B1-B1 of FIGS. 9a and 9B;

FIG. 10B is a sectional view taken along the plane B2-B2 in FIGS. 9a and 9B;

FIG. 11 is a CT picture of the junction of the inner side wall panel and the heat insulating prevention panel of example 4;

FIG. 12 is a CT picture of the junction of the inner side wall panel and the heat-insulating prevention panel in comparative example 2;

FIG. 13 is a photograph of a finished product of example 4 in which a conformal rubber is formed on an outer sidewall;

FIG. 14 is a photograph of a finished product of comparative example 3 in which the outer sidewall plate is formed without a conformal rubber;

FIG. 15 is a diagram illustrating a second transition buffer structure according to an embodiment of the present invention;

FIG. 16 is a flow chart of a method for forming a composite tubular article according to one embodiment of the present invention.

Reference numerals:

1, a heat-proof and insulating layer; an axial support structure 2; an inner-fillable structure 202; an outer reinforcing structure 203; a face plate 2031; a reinforcing rib 2032; an inner side wall panel 3; a radial filling structure 4; an outer side wall panel 5; a radial support structure 6; an outer coating 7; an outer coating body 701; an annular protrusion 702; a first transition buffer structure 8; a first rigid connection layer 801; a first malleable support layer 802; a second rigid link layer 803;9 carbon fiber fabric prepreg; rotating the carbon fiber fabric prepreg layer relative to the bottom layer by 90 degrees for a layer 901; a bottom carbon fiber fabric prepreg layer 902; rotating the carbon fiber fabric prepreg layer at an angle of 45 degrees in a counterclockwise direction relative to the bottom layer 903; rotating the carbon fiber fabric prepreg layer at an angle of 45 degrees clockwise relative to the bottom layer 904; a second transition buffer structure 10; a third rigid connection layer 1001; a second flexible support layer 1002; a fourth rigid connecting layer 1003; the outer side wall plate is externally provided with an accumulated glue and special-shaped area 11; a preform 12 to be formed; a vacuum bag 13; an autoclave 14; an autoclave inlet and outlet 1401; a mold 15; a vacuum extraction port 16.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention and not to limit its scope.

In order to clearly express the technical scheme of the invention, the following terms are specifically explained:

three-proofing paint: after curing, a layer of transparent protective film is formed, and the transparent protective film has excellent insulating, damp-proof, anti-creeping, shockproof, dustproof, anti-corrosion, anti-aging, corona-resistant and other performances.

Quasi-isotropy: the rigidity in all directions in the plane is the same, and the symmetrical laminated plate without the tension-shear or shear-tension coupling effect is different from the isotropic laminated plate in that: the rigidity in the thickness direction is not necessarily the same as the in-plane rigidity; its bending stiffness properties are also not isotropic.

Chopped strand mats: and the glass fiber fabrics are randomly distributed and bonded together after the glass fiber strands are chopped.

And (3) laminating and pasting fiber cloth: and (5) paving and bonding the fiber cloth in multiple layers.

Chopped strand mat needling pattern, fabric lamination needling: the carded chopped strand mat is needled in a needled form, the fabric laminate is needled, the fibers are mechanically entangled with each other, and the web is consolidated to produce a mat-like material.

The glass fiber cloth is various glass fiber cloth and glass fiber fabrics woven by glass fiber yarns.

Demolding cloth: the demolding cloth is an auxiliary material for the composite material member in the forming and curing process and is also one material set between the mold and the blank part to prevent the adhesion of resin to the mold.

Pressure equalizing plate: the pressure equalizing plate is a process auxiliary material in the forming and curing process of the composite material member, and is a material which is arranged between the die and the blank part and prevents the blank part from being stressed unevenly.

An empty isolation film: the auxiliary material mainly plays a role in positioning and fixing in the autoclave molding process, allows volatile components to pass through, and can absorb a certain amount of redundant resin; for less resin content, for example, prepreg vacuum forming processes, non-porous release films are often chosen.

Air-permeable felt: has good absorption performance. May absorb additional resin or act as a medium in the vacuum process.

A flow guide net: when the resin is used in a vacuum process, the resin is promoted to flow, and the resin is quickly and effectively dispersed in a net structure of the whole workpiece.

Shape following rubber: an uncured rubber material that is free to deform under pressure without active rebound.

A vacuum impregnation process: the vacuum application process is that under the vacuum condition, the impregnating material is impregnated into other solid matters through negative pressure so as to improve the material performance of the matters or meet certain specific requirements.

And (3) vacuum introduction process: laying glass fiber, glass fiber fabric, various inserts, demolding cloth, a resin permeable layer, a resin pipeline and a covering nylon and a flexible film (vacuum bag) on a cured gel coat layer; sealing the film and the forming cavity, vacuumizing, impregnating the fiber by resin flowing along a resin pipeline and the like, and further curing and forming.

In one aspect, the present invention provides a method for forming a composite tubular article, which is used for preparing the composite tubular article, as shown in fig. 16, and comprises the following steps:

step 1: dipping and molding the heat-proof and insulating layer 1, and preparing the heat-proof and insulating layer in a mould by adopting a vacuum dipping process;

specifically, a core mold and a prefabricated body of the thermal insulation layer are placed in a cylindrical cavity mold, resin is introduced into the cylindrical cavity mold, and a cylindrical cavity mold main body and a cover plate are locked in a bolt locking mode; the prefabricated body is fully infiltrated by resin by adopting a vacuum impregnation mode, and the vacuum degree of vacuum impregnation is not less than 980mbar; and (3) adopting a self-heating device to raise the temperature of the mould to 80-180 ℃ to cure the resin for 12-24 h, and obtaining the heat-proof layer after demoulding and processing.

The core mold is a cylindrical mold nested in the cylindrical cavity mold, and a cylindrical heat insulation layer is formed in the area between the core mold and the cylindrical cavity mold.

Step 2: laying a first transition buffer structure 8;

specifically, the outer surface of the thermal insulation layer is used as a reference surface, epoxy glue is coated on the surface of the thermal insulation layer, 2-3 layers of glass fiber mats are paved and pasted, 1-3 layers of glass fiber cloth are paved and pasted, 2-3 layers of glass fiber mats are paved and pasted, and an adhesive is sprayed between the paved layers to finish the paving of the first transition buffer structure.

Compared with the prior art, the step 2 adopts a structure that 2-3 layers of glass fiber felts are paved and adhered on the heat-proof layer, 1-3 layers of glass fiber cloth are paved and adhered, and 2-3 layers of glass fiber felts are paved and adhered, wherein the flexible structure of the glass fiber cloth greatly improves the stress difference and cracking caused by different expansion rates of two connected layers when the temperature changes, and a good stress buffer layer is integrally formed; the glass fiber felts close to the heat-insulating layer and the inner side wall plate are respectively and fixedly connected tightly, so that the defect that the glass fiber cloth body is not strong in strength and easy to have insufficient anti-shearing capability is effectively overcome. The glass fiber felt is in one of a chopped strand mat form, a chopped strand mat needling form and a fabric laminated needling form; the thickness of the glass fiber felt and the glass fiber cloth is the thickness of the common products in the market, and the invention is not specially limited.

And step 3: vacuum introduction molding of the inner side wall plate 3

Paving and sticking the fiber framework of the prefabricated body of the inner side wall plate, demolding cloth, an isolation film and a flow guide net on the outer wall of the first transition buffer structure in sequence from one side close to the heat-proof and insulating layer, arranging a glue injection pipeline and a glue outlet pipeline, installing a glue injection port and a glue outlet, paving a vacuum bag, vacuumizing to lock the vacuum bag, and gradually increasing the pressure within the range of 600-980 mbar after the negative pressure operation starts; further comprises the following steps:

step 3.1, conveying the prefabricated body of the inner side wall plate placed in the vacuum bag to heating equipment after vacuumizing, and setting the temperature of the heating equipment to be 120-130 ℃;

step 3.2, heating the resin to 100-120 ℃, and introducing the resin into the inner side wall plate prefabricated body;

and 3.3, after glue injection is finished, raising the temperature of the oven to 130-150 ℃, preserving heat for 3 hours, then raising the temperature of the oven to 170-180 ℃, preserving heat for 2 hours, cooling the product along with the oven, and polishing and cleaning the surface after demolding to obtain the inner side wall plate. The fiber framework of the prefabricated body of the inner side wall plate is one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber.

In the

steps

2 and 3, the selected resin can be high-temperature-resistant thermosetting resin, preferably high-temperature-resistant epoxy resin, phenolic resin and silicon resin; EH301 epoxy resin is more preferable.

Compared with the prior art, in the step 3, the resin is preheated to 100-120 ℃ and is lower than the heating temperature of the outer side wall plate preform in the oven by 120-130 ℃, after glue injection is finished, the temperature of the oven is raised to 130-150 ℃ and is kept for 3h, and then the temperature of the oven is raised to 170-180 ℃ and is kept for 2h; because resin and environmental heat dissipation are from resin outside to inside process, heat up resin in advance and be less than the temperature that outside lateral wall board preform set up at the oven, so the flow rate of resin outer wall relative inside can be accelerated in the temperature setting, help resin to minute structure dispersion and distribution, reduce starved and incompleteness, lower temperature can further reduce resin reaction rate simultaneously, is favorable to the resin dispersion even.

Compared with the prior art, the temperature setting is divided into three main stages: the initial temperature of the outer side wall plate preform set at the oven temperature is 120-130 ℃, and the oven temperature is further set at 130-150 ℃ and 170-180 ℃ for two subsequent stages. The corresponding staged setting of temperature more matches the resin flow, dispersion and curing laws: in the first stage, after glue injection, glue mainly flows in a main trunk and a large space, the resistance is small, the viscosity is reduced without intentionally raising the temperature, the fluidity is improved, and the curing is delayed by the lower temperature; in the second stage, the main resin is dispersed to a fine structure, and at the moment, because the resin is heated in the flowing process and is partially solidified to increase the viscosity and reduce the fluidity, the temperature needs to be properly increased to improve the fluidity; in the third stage, the second stage glue is fully dispersed and is cured to a higher degree at the same time, and at the moment, the temperature needs to be further increased to improve the curing crosslinking degree of the resin, so that the strength of the resin is improved.

And 4, step 4: forming the axial supporting structure 2, and preparing the axial supporting structure in a mould by adopting an autoclave process;

specifically, the method comprises the following steps:

step 4.1: casting the outer reinforcement structure 203 in the mold: as shown in fig. 5, a carbon fiber fabric prepreg is laid on the mold sprayed with the release agent as a face sheet 2031 of the outer reinforcing structure 203; the carbon fiber fabric prepreg is soaked by thermosetting resin, so that the carbon fiber fabric is fully coated by the thermosetting resin, and the thermosetting resin can be single-component epoxy resin. In order to ensure the bonding tightness of the fiber prepreg and the uniform thickness of each layer of the fiber prepreg, 3-5 layers of the fiber prepreg are paved and compacted in vacuum for 1 time; the time is 15min to 50min, and the range of 600mbar to 980mbar gradually increases after the negative pressure operation starts.

Compared with the prior art, the carbon fiber fabric prepreg laid and pasted is more beneficial to completely permeating carbon fibers with glue and obtaining more uniform effect compared with a carbon fiber glue injection process; 3-5 layers of fiber prepreg are paved and compacted for 1 time, which is beneficial to exhausting air and ensuring uniform force application and controlling the shape after molding.

Step 4.2: positioning the position of the internal fillable structure 202 on the panel 2031 by laser projection, and as shown in fig. 5, laying prepreg layer by layer on the foam shaped to conform to the shape as a reinforcing rib 2032 of the external reinforcing structure 203; after the laying of a layer of prepreg is finished, positioning by using a positioning tool, and performing pre-compaction treatment in a hot compaction mode, wherein the compaction temperature is 130-140 ℃, and the compaction time is 15-30 min; after all layers of prepreg are paved in sequence by the same method, the demolding cloth, the pressure equalizing plate, the isolating film with holes and the air-permeable felt are paved outside the outermost layer of prepreg in sequence and then are placed inside the vacuum bag with the air exhaust holes.

Compared with the prior art, the positioning tool is adopted to position and hot press each layer of prepreg after paving and pasting, so that the forming integrity can be ensured to the maximum extent, the positioning tool is used for replacing the vacuum bag-making forming process in the prior art, and only the vacuum pumping is carried out after all the prepregs are paved and pasted, so that the vacuum forming process is greatly simplified compared with the prior art; meanwhile, the positioning tool matched with the shape of the internal fillable structure 202 can greatly avoid the phenomenon that foam contacts with the panel 2031 to form fillet glue residue, and the stability of the designed shape is ensured.

Step 4.3: transferring the vacuum bag and the axial support structure in the vacuum bag to an autoclave, vacuumizing the vacuum bag to negative pressure, and gradually increasing the vacuum bag within the range of 600-980 mbar after the negative pressure operation starts; raising the temperature of the autoclave to 130-150 ℃ and preserving heat for 3-4 h, then raising the temperature of the autoclave to 170-180 ℃ and preserving heat for 2-4 h, wherein the molding pressure is 0.4-0.6 MPa; during which the vacuum bag is kept in a stable vacuum state; and cooling the crude product of the axial supporting structure along with a furnace, and trimming after demolding to obtain the axial supporting structure.

Compared with the prior art, the method has the advantages that the method of gradually increasing the pressure in the range of 600mbar to 980mbar after the beginning is adopted for the negative pressure operation, so that the vacuum pressure and the exhaust capacity are gradually improved along with the curing and viscosity increasing of the thermosetting resin, the continuous and stable pressure outside the vacuum bag on the resin-containing material in the curing process of the resin is ensured, and the phenomena of incapability of compression and larger forming thickness along with the viscosity increasing of the resin under the negative pressure condition are avoided; meanwhile, the problems of resin overflow and waste caused by overlarge vacuum pressure and high compression speed in the initial stage when the viscosity of the resin is low are avoided. Compared with the prior art, the crude product of the axial supporting structure is cooled along with the furnace, so that the temperature difference between the inside and the outside of the axial supporting device can be reduced as much as possible, and the stress generated by the foam and the external reinforcing structure due to different thermal expansion coefficients is avoided.

Further, the carbon fiber fabric prepreg according to the present invention can obtain a quasi-isotropic structure by adjusting the lay-up angle, and as the carbon fiber fabric prepreg must include at least 4 layers, and each layer must have the same rigidity and thickness. With initial setting bottom carbon fiber fabric prepreg for 0 layer, its fibre orientation of putting is initial zero degree, and the fibre of the relative bottom carbon fiber fabric prepreg of fibre direction of laying of all the other layers carbon fiber fabric prepreg is different and has certain inclination in the fibre of laying the plane internal direction, and the fibre of equidirectional not also has specific intensity, as shown in fig. 6:

bottom layer carbon fiber fabric prepreg layer (0 ° layer) 902: providing axial strength and stiffness, is well suited for assemblies that must withstand axial loads.

Counter-clockwise rotation of 45 ° plies (45 ° plies) 903 with respect to the bottom carbon fiber fabric prepreg ply: providing shear and torsional strength and stiffness.

Rotate 45 ° layers (-45 ° layers) 904 clockwise with respect to the bottom carbon fiber fabric prepreg layer: providing shear and torsional strength and stiffness.

Rotating the layers at 90 degrees (90 degree layers) 901 relative to the bottom carbon fiber fabric prepreg layer: provide lateral strength and stiffness, hold the layers together and provide resistance to compression.

Compared with the prior art, the carbon fiber fabric prepreg can obtain a quasi-isotropic structure by adjusting the laying angle, and has axial strength and rigidity, shear strength and torsional strength and rigidity, and shear strength and torsional strength and rigidity; quasi-isotropic structures can produce stiff materials with strength in all directions.

And 5: assembling the inner side wall plate and the axial support structure;

specifically, the preset position of the inner side wall plate which is guided in the step 3 is fixedly connected with an axial supporting structure, and a cylindrical part prefabricated body covered with the axial supporting structure is obtained; the outer surface of the inner side wall plate is roughened in an electric polishing mode, and the outer surface of the inner side wall plate is cleaned by acetone or ethanol serving as a cleaning agent.

The method comprises the steps of paving a glue film to a preset position in a laser projection mode, placing an axial supporting structure on the glue film, positioning the axial supporting structure, paving demolding cloth and an air felt, arranging an air suction opening and making a bag, transferring the axial supporting structure and an assembly to an oven, gradually increasing vacuum pressure within the range of 600-980 mbar, raising the temperature of the oven to 130-150 ℃ for heat preservation for 3 hours, raising the temperature of the oven to 170-180 ℃ for heat preservation for 2 hours to enable the glue film to be cured, and assembling the rest axial supporting structures in the same mode after demolding. And after the assembly is finished, processing the glue accumulation area to obtain a cylindrical workpiece with an axial support structure. The glue film selected in the step can be a high-temperature-resistant thermosetting resin glue film, preferably high-temperature-resistant epoxy resin and silicon resin; the more preferable adhesive film is an adhesive film EH601 high-temperature resistant structural adhesive film; the thickness of the adhesive film is 0.1 mm-0.2 mm, and the number of the adhesive film layers is 1-2.

Step 6: radial packing and radial support structure fixation

Bonding and fixing a radial filling structure on the outer wall of the cylindrical part prefabricated body covered with the axial support structure; and further bonding and fixing a radial supporting structure on the outer wall of the radial filling structure, and curing and molding under vacuum to obtain a cylindrical part preform with the radial filling structure and the radial supporting structure.

Specifically, the method comprises the following steps:

step 6.1: fixing the cut and formed radial filling structure on the inner side wall plate coated with the adhesive, further positioning a radial supporting structure of the radial supporting structure on the outer wall of the radial filling structure by adopting a positioning tool, paving a glass fiber prepreg between the radial supporting structure and the radial filling structure, sequentially paving demolding cloth, an isolating film and an air-permeable felt on the rest side surface of the radial supporting structure, and placing the radial supporting structure, the initial cylindrical workpiece in a vacuum bag and arranging an air exhaust port; the glass fiber prepreg is made of glass fiber, and the invention is not specially limited; the resin selected in the glass fiber prepreg can be high-temperature-resistant thermosetting resin, preferably one or more of phenolic resin, organic silicon resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin or modified resin of phenolic resin, organic silicon resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin; EH301 epoxy resin is more preferable.

The schematic diagram of the vacuum impregnation process or vacuum introduction process is shown in fig. 4: placing the preform 12 to be formed inside a vacuum bag 13; the vacuum bag 13 with the preform 12 to be formed and the mould 15 are sealingly placed in the autoclave 14 and externally connected to the autoclave 14 via vacuum extraction openings 16. The autoclave 14 is provided with an autoclave inlet and outlet 1401, and pressure-adjustable hot compressed gas can be introduced through the autoclave 14 inlet and outlet 1401 to adjust the internal pressure and temperature of the autoclave 14; when the vacuum bag 13 is vacuumized, the autoclave 14 is filled with air to press the vacuum bag 13 and the preform 12 to be molded, thereby completing the hot press forming of the preform 12 to be molded.

Compared with the prior art, the isolating membrane and the breathable felt are added in the step, so that a larger amount of resin can be absorbed, the diversion effect on the redundant resin is achieved, and the influence on the appearance of a finished product due to the accumulation of the redundant resin is prevented.

Step 6.2: preserving the heat of the vacuum bag and the initial cylindrical part at the temperature of 130-150 ℃ for 2-6 h, and further heating to the temperature of 170-180 ℃ for 1-4 h to solidify the prepreg; compared with the prior art, the step adopts a two-stage heating process, controls the flowing and curing rate of the resin, and cures the resin after the resin flows and disperses fully; too fast curing of the resin can lead to insufficient polymerization flow and uneven dispersion can lead to partial gel loss; and the first temperature rise time is too long, so that the content of residual effective glue in the glass fiber prepreg is low, and the improvement of the connection strength between the radial support structure and the initial cylindrical part is not facilitated.

And 7: laying a second transition buffer structure

And (4) paving and pasting 2-3 layers of glass fiber felts on the radial supporting structure fixed in the step (6), paving and pasting 1-3 layers of glass fiber cloth, paving and pasting 2-3 layers of glass fiber felts, and finishing the paving of the second transition buffer structure.

And step 8: vacuum introduction molding of outer side wall plate

And preparing the outer side wall plate on the outer side of the second transition buffer structure after the second transition buffer structure is laid by adopting a vacuum introduction process on the outer wall of the cylindrical part prefabricated body with the radial support structure.

The inventor finds that: different in-situ foaming processes of PEI (polyetherimide) foam, PMI (polymethacrylimide) foam and common foam, the prior art adopts a process of pre-forming, cutting and assembling, and the outer sidewall plate 5 is thermoset-formed, and the following defects are present, as shown in fig. 3:

(1) Edge glue accumulation of the radial support structure;

(2) The corner appearance of the radial support structure is special-shaped.

Fig. 2 shows the normal state without glue build-up, fig. 3 shows the presence of glue build-up and a profiled situation, where 5 shows the outer side wall panel and 11 is the outer glue build-up and profiled area of the outer side wall panel.

The defects seriously affect the use of products, and are also main influencing factors that PEI (polyetherimide) foam and PMI (polymethacrylimide) foam cannot be directly used for reducing weight of a supporting structure in the prior art.

In order to overcome the defects, the invention also provides a method for forming the outer side wall plate of the cylindrical part with the radial support structure, which comprises the following steps:

paving and sticking the fiber framework, the demolding cloth, the isolating film and 2 layers of the flow guide net of the prefabricated body of the outer side wall plate on the outer side of the laid second transition buffer structure; when the demolding cloth and the flow guide net are paved and adhered, the round corners need to be cut off for lapping treatment, conformal rubber is placed at the round corners, and the round corner quality of the outer side wall plate is guaranteed; arranging a glue injection pipeline and a glue outlet pipeline, installing a glue injection port and a glue outlet, laying a vacuum bag film, vacuumizing to lock the vacuum bag film, conveying the outer side wall plate preform to heating equipment, setting the temperature of an oven to be 120-130 ℃, heating resin to be 100-120 ℃, introducing the resin into the outer side wall plate preform, after glue injection is finished, heating the temperature of the oven to be 130-150 ℃, keeping the temperature for 3 hours, then heating the temperature of the oven to be 170-180 ℃, keeping the temperature for 2 hours, cooling the product along with the oven, polishing and cleaning the surface after demolding to obtain the outer side wall plate. The outer side wall plate preform fiber is one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber.

In the heat-proof layer, a fiber reinforced structure layer can be arranged between resin matrix material layers. Specifically, the fiber reinforced structural layer adopts one or more of a fiber woven structural layer, a fiber cloth laminated paving layer, a short cut felt needled layer and a fabric laminated needled layer. The resin selected in the step can be one or more of phenolic resin, organic silicon resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin, or one or more of modified resins of phenolic resin, organic silicon resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin, preferably high-temperature-resistant epoxy resin, phenolic resin and silicon resin; EH301 epoxy resin is more preferable.

Compared with the prior art, the embodiment adopts the steps that 2-3 layers of glass fiber felts are paved and adhered on the radial supporting structure or the radial filling structure, 1-3 layers of glass fiber cloth are paved and adhered, and 2-3 layers of glass fiber felts are paved and adhered, so that the second transition buffer structure is constructed, the stress difference and the cracking caused by different expansion rates of the outer side wall plate and the radial supporting structure or the radial filling structure during temperature change are greatly improved by the flexible structure of the glass fiber cloth, and a good stress buffer layer is integrally formed; and the glass fiber felts close to the outer side wall plate, the radial supporting structure and the radial filling structure are respectively and fixedly connected tightly, so that the defects of low strength and insufficient shearing resistance of the glass fiber cloth body are effectively overcome.

Compared with the prior art, in the step 8, the resin is preheated to 100-120 ℃ and is lower than the heating temperature of the outer side wall plate preform in the oven by 120-130 ℃, after glue injection is finished, the temperature of the oven is raised to 130-150 ℃ and is kept for 3h, and then the temperature of the oven is raised to 170-180 ℃ and is kept for 2h; because resin and environmental heat dissipation are from the outside to inside process of resin, heat up resin in advance and be less than the temperature that outside lateral wall board preform set up at the oven, so the flow rate of resin outer wall relative inside can be accelerated in the temperature setting, help resin to minute structure dispersion and distribution, reduce starvation and incompleteness, the lower temperature can further reduce resin reaction rate simultaneously, is favorable to the resin dispersion even.

Compared with the prior art, the temperature setting is divided into three main stages: the method comprises a first stage of setting the initial temperature of the outer side wall plate preform at the temperature of an oven to be 120-130 ℃, and further setting the temperature of the oven to be 130-150 ℃ and 170-180 ℃ for two subsequent stages. The corresponding phased setting of temperature more matches the resin flow, dispersion and curing laws: in the first stage, after glue injection, glue mainly flows in a main trunk and a large space, the resistance is small, the viscosity is reduced without intentionally raising the temperature, the fluidity is improved, and the curing is delayed by the lower temperature; in the second stage, the main resin is dispersed to a fine structure, and at the moment, because the resin is heated in the flowing process and is partially solidified to increase the viscosity and reduce the fluidity, the temperature needs to be properly increased to improve the fluidity; in the third stage, the second stage glue is fully dispersed and is cured to a higher degree at the same time, and at the moment, the temperature needs to be further increased to improve the curing crosslinking degree of the resin, so that the strength of the resin is improved.

Compared with the prior art, when the demolding cloth and the flow guide net are paved and adhered, the round corners need to be cut off for lapping treatment, the glue outflow rate of most of the residual glue can be greatly increased, and the accumulated glue is reduced; on the other hand, the conformal rubber is placed at the round corner, so that the problems that the pressure applied by the vacuum bag at the round corner is small and the vacuum bag cannot be effectively tightened during vacuum pumping can be greatly solved, the vacuum bag applies pressure through the conformal rubber to promote glue discharge, and glue accumulation is reduced; meanwhile, due to the characteristic that the shape following rubber is shaped without resilience after being pressed, the stable quality of the round corner shape design of the outer side wall plate is ensured.

And step 9: three-proofing coating:

and brushing three-proofing paint on the surface of the cylindrical prefabricated part with the outer side wall plate as an external coating.

On the other hand, the invention provides a composite material cylindrical part, as shown in fig. 1, which comprises an insulating layer 1, a first transition buffer structure 8, an inner side wall plate 3, a radial filling structure 4 and an outer side wall plate 5 which are arranged in sequence from inside to outside; the first transition buffer structure 8 is a multi-layer composite structure comprising a flexible support layer capable of matching the thermal barrier layer 1 and the inner sidewall plate 3 having different coefficients of thermal expansion.

Compared with the prior art, the first transition buffer structure is arranged between the thermal insulation layer and the inner side wall plate, the stress difference and cracking caused by different expansion rates of the thermal insulation layer and the inner side wall plate are greatly improved by the flexible structure of the toughness supporting layer, and a good stress buffer layer is integrally formed.

Wherein the thermal expansion coefficient difference between the thermal insulation layer 1 and the inner side wall plate 3 is 8 multiplied by 10 ^-6 m/℃～9×10 ^-6 Between m/DEG C, the first transition buffer structure 8 is a multilayer composite structure and is fixedly connected with the outer wall of the heat-proof and insulation layer 1, the inner side wall plate 3 is fixedly connected with the outer wall of the first transition buffer structure 8, and the radial filling structure 4 is fixedOn the outer wall of the inner side wall plate 3. The problem that different thermal expansion coefficients are easy to crack in the prior art when the temperature difference is high is solved through the arrangement of the first transition buffer structure, and compared with the prior art, the shearing strength of the inner side wall is improved to 60MPa from 55 MPa.

Specifically, a first transition buffer structure 8 is arranged between the inner side wall plate 3 and the heat insulation preventing layer 1, as shown in fig. 1 and 7, the first transition buffer structure 8 includes a first rigid connection layer 801, a first tough support layer 802 and a second rigid connection layer 803 which are sequentially distributed from a high temperature region to a low temperature region; first rigid connection layer 801, first malleable support layer 802, and second rigid connection layer 803 are joined by an adhesive. Wherein, the first rigid connecting layer 801 is fixedly connected with the outer wall of the heat-proof and insulation layer 1, and the second rigid connecting layer 803 is fixedly connected with the inner wall of the inner side wall plate 3.

The first rigid connection layer 801 and the second rigid connection layer 803 may be glass fiber mats; selecting a glass fiber mat with the fiber length of 2-10 mm as the glass fiber mat; chopped strands are selected as the glass fiber mats. Namely, the first transition buffer structure 8 adopts a transition buffer structure of glass fiber mat, glass fiber cloth and glass fiber mat.

The first flexible supporting layer can be glass fiber cloth; the glass fiber cloth can be selected as follows: the cloth is composed of grain cloth, twill cloth, and plain cloth, preferably twill cloth with good shear-resistant tensile property, preferably 170g/cm ³ ～220g/cm ³ Twill cloth. The glass fiber cloth with the overweight gram number has larger thickness or too dense weaving density, which is not beneficial to the entering of the adhesive to play the adhesive role and the improvement of the adhesive strength; the glass fiber cloth with too light gram number has smaller thickness or too small weaving density, and the glass fiber cloth has too small strength, thus being not beneficial to improving the bonding strength.

The adhesive comprises: high-temperature-resistant epoxy glue powder, a high-temperature-resistant toughening agent and a high-temperature-resistant diluent; the high-temperature-resistant epoxy glue powder can be EH301 epoxy resin; the dosage and mass ratio of the high-temperature-resistant epoxy glue powder, the high-temperature-resistant toughening agent and the high-temperature-resistant diluent is as follows: 1: 0.05-0.3.

Preferably, the thermal insulation layer 1 has an expansion coefficient of 0.13 × 10 ^-6 m/℃～0.2×10 ^-6 m/DEG C, and the coefficient of expansion of the material of the inner side wall plate 3 is not more than 9 x 10 ^-6 m/℃. The thermal expansion coefficient ranges of the thermal insulation preventing layer 1 and the inner side wall plate 3 need to be controlled within a proper range, and the difference is too large, so that the thermal insulation preventing layer is not matched with the first flexible supporting layer.

Specifically, the first rigid connection layer 801 of the first transition buffer structure 8 includes 2 to 3 layers of glass fiber mats, the first flexible support layer 802 includes 1 to 3 layers of glass fiber cloth, and the second rigid connection layer 803 includes 2 to 3 layers of glass fiber mats. The first transition buffer structure 8 can adopt a mode of sequentially paving and pasting layers, for example, paving and pasting 2-3 layers of glass fiber felts on the heat-proof layer, then paving and pasting 1-3 layers of glass fiber cloth, and then paving and pasting 2-3 layers of glass fiber felts, the first transition buffer structure is constructed through the mode, wherein the stress difference and cracking caused by different expansion rates of the heat-proof layer and the inner side wall plate during temperature change are greatly improved through the flexible structure of the glass fiber cloth, and a good stress buffer layer is integrally formed; the glass fiber felts close to the heat-insulating layer and the outer side wall plate are respectively and fixedly connected tightly, so that the defects of low strength and insufficient shearing resistance of the glass fiber cloth body are effectively overcome.

Specifically, the matrix resin of the heat-proof and insulating layer may be one or more of phenolic resin, silicone resin, silicon-containing aryne resin and aryl acetylene resin, or one or more of modified resins of phenolic resin, silicone resin, silicon-containing aryne resin and aryl acetylene resin.

Compared with the prior art, the resin has better high-temperature stability and strength: the phenolic resin, the silicon-containing aryne resin and the arylacetylene resin contain aromatic group structures, and have better rigidity and high temperature resistance; meanwhile, the organic silicon resin and the silicon-containing aryne resin contain heat-resistant silicon-oxygen bonds which have better thermal stability than carbon-oxygen bonds.

Preferably, the resin is hybrid phenolic resin PF-45, namely interpenetrating phase composite material modified phenolic resin, the surface of the resin can be ceramic-shaped at high temperature, so that the resin has better heat insulation performance, and meanwhile, the resin has a uniform nano-pore structure inside the resin, so that the heat insulation performance is further improved.

Preferably, the heat-proof and insulating layer adopts a fiber reinforced resin matrix structure, and the fiber is one or a mixture of more of quartz fiber, carbon fiber, high silica fiber and basalt fiber. Wherein, carbon fiber, quartz fiber have hollow structure, have light characteristics. Specifically, the fiber reinforced resin matrix composite material can be prepared by filling the resin matrix with the reinforced fibers.

Compared with the prior art, the strength, rigidity and abrasion resistance of the heat-proof layer can be greatly improved by adding the reinforcing material into the resin matrix, and the heat-proof layer body is not easy to damage and rub to fall off; meanwhile, the reinforced material is beneficial to improving the glass transition temperature of the heat-proof layer, so that the high-temperature resistance is improved.

Preferably, in the heat insulation prevention layer, a fiber reinforced structure layer can be arranged between resin matrix material layers. Specifically, the fiber reinforced structural layer adopts one or more of fiber woven structural layer, fiber cloth laminated paving layer, chopped strand mat needling layer and fabric laminated needling layer.

The fabric laminated needling is to penetrate the fabric laminated layer to form a needling structure, so that the bonding strength between layers in the thermal insulation layer is further improved through the fabric laminated needling, and the anti-falling capacity of the thermal insulation layer is further improved.

The inner side wall plate 3 can adopt resin matrix material layers to arrange fiber reinforced structure layers; the fiber reinforced structure can be one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber, and is preferably carbon fiber. The resin is any one of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin, epoxy resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin, arylacetylene resin and epoxy resin, and EH301 epoxy resin is preferred.

An axial supporting structure 2 is also arranged between the inner side wall plate 3 and the outer side wall plate 5; axial bearing structure 2 is in radial filling structure 4 inside and be fixed in the outer wall of interior lateral wall board 3, and axial bearing structure 2 is equipped with a plurality ofly and at the radial interval distribution of tube-shape finished piece, can effectively improve axial bending resistance and anti shear strength.

The axial support structure 2 comprises an inner-fillable structure 202 and an outer reinforcing structure 203 surrounding the inner-fillable structure 202; the outer reinforcing structure 203 includes a face plate 2031 fixedly attached to the inner sidewall plate 3 and a bead 2032 surrounding the fixed inner fillable structure 202.

The face plate 2031 and the reinforcing ribs 2032 can adopt resin matrix material layers to arrange fiber reinforced structure layers; the fiber reinforced structure can be one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber, and is preferably carbon fiber. The resin is any one of phenolic resin, silicone resin, silicon-containing aryne resin, aryl acetylene resin, epoxy resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin, and preferably EH301 epoxy resin.

The inner-fillable structure 202 may be a low density material; further, a solid material or a hollow material with hollow pores or bubbles can be selected; the hollow material is preferably one or a combination of high temperature resistant PEI foam and PMI foam.

The inner inflatable structure 202 and the outer reinforcing structure 203 can be selected from different materials; the axial support structure of the cylindrical part can be arranged in the following mode: a plurality of independent axial support structures are uniformly arranged along the circumferential direction of the cylindrical part or a plurality of axial support structure groups are uniformly arranged along the circumferential direction of the cylindrical part, that is, a plurality of independent axial support structures or a plurality of axial support structures can be arranged to form a plurality of axial support structure groups.

Specifically, when a plurality of independent axial support structures 2 are uniformly arranged along the circumferential direction of the cylindrical workpiece, a gap exists between adjacent axial support structures 2; when a plurality of axial support structure groups are uniformly arranged along the circumferential direction of the cylindrical part, gaps exist between adjacent axial support structure groups, and gaps or no gaps exist among a plurality of axial support structures in the axial support structure groups. Illustratively, as shown in fig. 1, 3 axial support structures are grouped to form an axial support structure group, and 4 axial support structure groups are uniformly arranged along the circumferential direction of the cylindrical part.

It should be noted that, the plurality of axial support structures in each axial support structure group may be integrally formed or may be separately formed. When a plurality of axial supporting structures in each axial supporting structure group are integrally formed, the common panel 2031 of the plurality of axial supporting structures is integrally paved, the positions of the plurality of filling structures 202 are positioned on the common panel 2031, and then the reinforcing ribs 2032 of the external reinforcing structures 203 of the plurality of axial supporting structures are integrally paved, so that the integrally formed axial supporting structure group is formed, and at the moment, no gap exists between the plurality of axial supporting structures in the axial supporting structure group.

Compared with the prior art, the introduction of the fiber reinforced structure enhances the strength of resin, simultaneously reduces the fluidity of the resin, improves the molding processing convenience of the axial supporting structure 2 and the inner side wall plate 3 and expands the types of machinable shapes; meanwhile, due to the introduction of the fiber reinforced structure, the plurality of axial support structures 2 share the fiber reinforced structure, so that the connection of the plurality of axial support structures 2 is easier to realize, and an axial support structure 2 assembly with higher strength is obtained. Further, between the outer wall of the radial filling structure 4 and the outer side wall plate 5, a plurality of radial support structures 6 are distributed at intervals along the axial direction of the cylindrical part, as shown in fig. 1: the radial supporting structures 6 can be 2-5 pieces, and the radial bending resistance and the shear strength can be effectively improved.

Further, the interior of the radial filling structure 4, the axial support structure 2 and the radial support structure 6 may be filled with a material of lower density, with a lower overall weight; meanwhile, the axial support structure 2 and the radial support structure 6 can be filled with light materials with hollow micro-pores or bubble structures, so that the energy transfer rate is reduced while the weight is low, and the heat insulation and sound insulation effects are achieved. On one hand, the hollow structure contains gas and has better heat insulation effect than a solid material; on the other hand, the sound wave is refracted or reflected at the gas-solid interface of the hollow structure and then interferes with the incident sound wave to achieve the silencing effect.

Compared with the prior art, the tubular part of the support structure of the embodiment has higher radial and axial bending resistance and shear strength, and in addition, the materials of the external reinforcing structure 203, the thermal insulation preventing layer 1, the external inner side wall plate 2 and the external side wall plate 5 which are lower in density than the axial support structure 2 can be filled in the radial filling structure 4, the axial support structure 2 and the radial support structure 6, so that the overall weight is lower.

The low-density material can be selected from a solid material or a hollow material with hollow air holes or air bubbles; the hollow material is preferably one or the combination of high-temperature-resistant PEI (polyetherimide) foam and PMI (polymethacrylimide) foam, and the defects of large mass and rapid energy transfer loss of the traditional support structure are overcome. Specifically, the radial filling structure 4, the radial supporting structure 6 and the internal filling structure 202 are made of high-temperature-resistant PEI (polyetherimide) foam sold in the market, and the porosity is 50-70%.

As shown in fig. 1, where the radial support structure 6 is provided, the outer sidewall plate 5 is fixedly connected with the radial support structure 6 through a second transition buffer structure 10; where the radial support structure 6 is not provided, the outer sidewall plate 5 is fixedly connected with the radial filling structure 4 through the second transition buffer structure 10. The outer side wall panels 5 may further serve a supporting and insulating function.

The outer side wall plate 5 can be selected from inorganic non-metallic materials with stronger rigidity, metals, thermoplastic resins and thermosetting resins; from the viewpoint of weight reduction, thermoplastic resins and thermosetting resins are preferable; from the viewpoint of enhancing rigidity at normal temperature and high temperature, a thermosetting resin material is preferable.

The outer side wall plate 5 can adopt a resin matrix material layer to arrange a fiber reinforced structure layer; the fiber reinforced structure can be one or more of quartz fiber, carbon fiber, high silica fiber and basalt fiber, and is preferably carbon fiber. The resin is any one of phenolic resin, silicone resin, silicon-containing aryne resin, aryl acetylene resin, epoxy resin or modified resin of phenolic resin, silicone resin, silicon-containing aryne resin, aryl acetylene resin and epoxy resin, and preferably EH301 epoxy resin.

Compared with the prior art, the second transition buffer structure is arranged between the radial support structure and the outer side wall plate, the stress difference and cracking caused by different expansion rates of the radial support structure and the outer side wall plate in temperature change are greatly improved by the flexible structure of the toughness support layer, and a good stress buffer layer is integrally formed.

Wherein the outer side wall plate 5 and the radial support structureThe difference in the coefficients of thermal expansion of the structure 6 or the radial filling structure 4 is 35 x 10 ^- ⁶ m/℃～41×10 ^-6 Between m/DEG C, the second transition buffer structure 10 is a multilayer composite structure, and the inner wall of the second transition buffer structure 10 is fixedly connected to the outer wall of the radial support structure 6 or the radial filling structure 4. The second transition buffer structure solves the problem that different thermal expansion coefficients are easy to crack in the prior art when the temperature difference is high, and the shearing strength of the outer side wall is improved to 70MPa from 60MPa compared with the prior art.

Specifically, a second transition buffer structure 10 is arranged between the outer sidewall plate 5 and the radial support structure 6 or the radial filling structure 4, as shown in fig. 1 and fig. 15, the second transition buffer structure 10 includes a third rigid connection layer 1001, a second flexible support layer 1002 and a fourth rigid connection layer 1003 which are sequentially distributed from a high temperature region to a low temperature region; the third rigid connection layer 1001, the second malleable support layer 1002, and the fourth rigid connection layer 1003 are connected by an adhesive. Wherein the third rigid connecting layer 1001 is fixedly connected with the outer wall of the radial support structure 6 or the radial filling structure 4, and the fourth rigid connecting layer 1003 is fixedly connected with the inner wall of the outer sidewall plate 5.

Third rigid connecting layer 1001 and fourth rigid connecting layer 1003 may be glass fiber mats; selecting a glass fiber felt with a fiber length of 10-15 mm and a better flow guide effect; chopped strands are selected as the glass fiber mats. Namely, the second transition buffer structure 10 adopts a transition buffer structure of glass fiber mat, glass fiber cloth and glass fiber mat.

The second flexible supporting layer can be glass fiber cloth; the glass fiber cloth can be selected from: the cloth is composed of grain cloth, twill cloth, and plain cloth, preferably twill cloth with good shear-resistant tensile property, preferably 170g/cm ³ ～220g/cm ³ Twill cloth. The glass fiber cloth with the excessive gram number has larger thickness or the too dense weaving density, which is not beneficial to the adhesive to enter and play the bonding function and the improvement of the bonding strength; the glass fiber cloth with too light gram number has smaller thickness or too small weaving density, and the glass fiber cloth has too small strength and is not beneficial to improving the bonding strength.

Preferably, because the outer side wall plate 5 and the radial support structure 6 or the radial filling structure 4 are positioned outside the cylindrical workpiece, the temperature difference between layers is far smaller than that between the heat-proof and insulation layer 1 and the inner side wall plate 3; the difference in the coefficient of thermal expansion of the actual radial support structure 6 or radial filling structure 4 and the outer side wall panel 5 allows a larger range, the coefficient of expansion of the outer side wall panel 5 being 9 x 10 ^-6 m/℃～15×10 ^-6 The material expansion coefficient of the radial support structure 6 or the radial filling structure 4 is not more than 50 multiplied by 10 between m/DEG C ^-6 m/DEG C. The thermal expansion coefficient ranges of the thermal insulation layer 1 and the inner side wall plate 3 need to be controlled within a proper range, and the difference is too large, so that the thermal insulation layer is not matched with the second flexible supporting layer.

Specifically, the third rigid connection layer 1001 of the second transition buffer structure 10 includes 2 to 3 layers of glass fiber mats, the second flexible support layer 1002 includes 1 to 3 layers of glass fiber cloth, and the fourth rigid connection layer 1003 includes 2 to 3 layers of glass fiber mats. The second transition buffer structure 10 can adopt a mode of sequentially laying and pasting layers, such as laying and pasting 2-3 layers of glass fiber mats on a radial supporting structure or a radial filling structure, then laying and pasting 1-3 layers of glass fiber cloth, and then laying and pasting 2-3 layers of glass fiber mats, so that the second transition buffer structure is constructed, wherein the stress difference and cracking caused by different expansion rates of an outer side wall plate and the radial supporting structure or the radial filling structure during temperature change are greatly improved by the flexible structure of the glass fiber cloth, and a good stress buffer layer is integrally formed; and the glass fiber felts close to the outer side wall plate, the radial supporting structure and the radial filling structure are respectively and fixedly connected tightly, so that the defects of low strength and insufficient anti-shearing capability of the glass fiber cloth body are effectively overcome.

In order to further improve the corrosion resistance, water resistance and antistatic performance of the cylindrical part, an external coating 7 can be arranged outside the outer side wall plate 5, and the external coating 7 can be made of a conformal coating material.

In order to illustrate the technical progress of the invention, GB/T3139-2005 "test method for thermal conductivity of fiber reinforced plastics" was further adopted to test the thermal conductivity of the thermosetting resin material involved in the invention.

In order to illustrate the technical progress of the invention, GB/T1450.1-2005 shear strength test method between layers of fiber reinforced plastics is further adopted to test the shear strength of the thermosetting resin material related to the invention.

To illustrate the technological advances of the present invention, the following examples and comparative examples are further disclosed:

example 1

The present embodiment discloses a method for forming a composite material tubular product, which is used for processing the composite material tubular product, and as shown in fig. 16, the method includes:

step 1: dip forming of heat-proof layer

Placing a core mould and a prefabricated body into a cylindrical cavity mould, introducing resin into the circular cavity mould, locking a cylindrical cavity mould main body and a cover plate in a bolt locking mode, fully soaking the prefabricated body by the resin in a vacuum impregnation mode, curing the resin for 24 hours by raising the temperature of the mould to 90 ℃ by a self-heating device and demoulding and processing to obtain the heat-insulating prevention layer, wherein the vacuum impregnation degree is not lower than 980 mbar. The core mold is a cylindrical mold nested in the cylindrical cavity mold, and a cylindrical heat insulation layer is formed in the area between the core mold and the cylindrical cavity mold.

Step 2: lay first transition buffer structure

Coating epoxy glue on the surface of the thermal-protective layer serving as a reference surface, paving and sticking 3 layers of glass fiber felts, paving and sticking 3 layers of glass fiber cloth, paving and sticking 3 layers of glass fiber felts, and spraying an adhesive between the paved layers to finish the paving of the first transition buffer structure.

And 3, step 3: vacuum introduction molding of inner side wall plate

Paving and pasting a prefabricated fiber framework of the inner side wall plate of the carbon fiber fabric on the outer side of the first transition buffer structure after the paving is finished, compacting for 1 time in vacuum by paving and pasting 3-5 layers of demolding cloth, an isolating film and a flow guide net in sequence, arranging a glue injection pipeline and a glue outlet pipeline, installing a glue injection port and a glue outlet, paving a vacuum bag film and vacuumizing to lock the vacuum bag film; and (3) conveying the inner side wall plate preform to heating equipment, setting the temperature of an oven to be 130 ℃, heating the resin to 120 ℃, introducing the resin into the inner side wall plate preform, heating the oven to 150 ℃ for heat preservation for 3h after glue injection is finished, heating the oven to 180 ℃ for heat preservation for 2h, cooling the product along with the oven, and polishing and cleaning the surface after demoulding to obtain the inner side wall plate. The binder comprises: EH301 epoxy resin glue powder, a high-temperature resistant toughening agent and a high-temperature resistant diluent; the dosage mass ratio is as follows: 1: 0.31; can be used at 100 deg.C for a long time without aging. The resin selected for use in this step is EH301 epoxy resin. The fiber framework of the prefabricated body of the inner side wall plate is made of carbon fiber.

And 4, step 4: axial support structure forming

Step 4.1: casting the external reinforcement structure 203 in the mold: laying carbon fiber fabric prepreg on the mold sprayed with the release agent to serve as a panel 2031 of the external reinforcing structure 203; the carbon fiber fabric prepreg is soaked by thermosetting resin, so that the carbon fiber fabric is fully coated by the thermosetting resin, and the thermosetting resin is EH301 epoxy resin. In order to ensure the bonding tightness of the fiber prepreg and the uniform thickness of each layer of the fiber prepreg, 3 layers of the fiber prepreg are paved and compacted in vacuum for 1 time; the time is 50min, and the negative pressure operation is gradually increased within the range of 980mbar after the start of the negative pressure operation.

Step 4.2: positioning the position of the inner fillable structure 202 on the face sheet 2031 by laser projection, as shown in fig. 5, laying prepreg layer by layer on the foam shaped into a suitable shape as a reinforcing rib 2032 of the outer reinforcing structure 203; after the layer of prepreg is laid and attached, positioning by using a positioning tool, and performing pre-compaction treatment in a hot compaction mode, wherein the compaction temperature is 140 ℃, and the time is 50min; after all layers of prepreg are paved in sequence by the same method, the demolding cloth, the pressure equalizing plate, the isolating film with holes and the air-permeable felt are paved outside the outermost layer of prepreg in sequence and then are placed inside the vacuum bag with the air exhaust holes.

Step 4.3: transferring the vacuum bag and the axial support structure in the vacuum bag to an autoclave, vacuumizing the vacuum bag to negative pressure, and gradually increasing the vacuum bag within the range of 600mbar to 980mbar after the negative pressure operation starts, wherein the increasing rate is 5mbar/min; raising the temperature of the autoclave to 130 ℃, preserving heat for 3 hours, then raising the temperature of the autoclave to 170 ℃, preserving heat for 2 hours, and forming pressure is 0.4MPa; during which the vacuum bag is kept in a stable vacuum state; and cooling the crude product of the axial supporting structure along with a furnace, and trimming after demolding to obtain the axial supporting structure.

And 5: assembly inner side wall plate and axial support structure

Finishing the preset position fixed connection axial bearing structure of the leading-in inner side wall plate in step 3, roughening the outer surface of the inner side wall plate in an electric polishing mode, cleaning the outer surface of the inner side wall plate by using a cleaning agent acetone, laying a glue film to the preset position in a laser projection mode, placing the axial bearing structure on the glue film, positioning the axial bearing structure by using a glue joint tool, sequentially laying demoulding cloth, arranging an air-permeable felt, arranging an air suction opening and making a bag, transferring the assembly to a drying oven, raising the temperature of the drying oven to 150 ℃ for heat preservation for 3h, raising the temperature of the drying oven to 180 ℃ for heat preservation for 2h to solidify the glue film, and assembling the rest axial bearing structures in the same mode after demoulding. And after the assembly is finished, processing the glue accumulation area to obtain a cylindrical workpiece with an axial support structure. The adhesive film is an adhesive film EH601 high-temperature-resistant structure adhesive film; the thickness of the adhesive film is 0.1mm, and the number of the adhesive film layers is 2.

Step 6: radial packing and radial support structure fixation

Brushing epoxy glue on the outer wall of the cylindrical part of the axial support structure prepared in the step 4 in the forming method of the cylindrical part of the axial support structure, and bonding the cut foam as a radial filling structure 4; further positioning a radial support structure on the outer wall of the radial filling structure 4, laying glass fiber prepreg between the radial support structure and the initial cylindrical part, laying demolding cloth, an isolation film and an air felt on the other side faces of the radial support structure in sequence, placing the radial support structure after laying and the initial cylindrical part in a vacuum bag and arranging an air exhaust port; the resin in the glass fiber prepreg is EH301 epoxy resin; and (3) insulating the vacuum bag and the initial cylindrical part at 150 ℃ for 3h, and further heating to 180 ℃ and insulating for 2h to cure the prepreg.

And 7: laying a second transition buffer structure

And (5) paving and pasting 3 layers of glass fiber felts on the radial supporting structure which is installed in the step (6), paving and pasting 1 layer of glass fiber cloth, paving and pasting 3 layers of glass fiber felts, and finishing the paving of the second transition buffer structure.

And 8: vacuum introduction molding of outer side wall plate

Paving and pasting an outer side wall plate prefabricated body fiber framework outside the second transition buffer structure after paving, paving and pasting 3-5 layers of vacuum compaction 1 time each time, paving and pasting demolding cloth, an isolating film and 2 layers of flow guide nets in sequence, cutting off a fillet when paving and pasting the demolding cloth and the flow guide nets, performing lap joint treatment, placing conformal rubber at the fillet, and ensuring the fillet quality of the outer side wall plate; arranging a glue injection pipeline and a glue outlet pipeline, installing a glue injection port and a glue outlet, laying a vacuum bag film, vacuumizing to lock the vacuum bag film, conveying the outer side wall plate preform to heating equipment, setting the temperature of a drying oven to 130 ℃, heating resin to 110 ℃, introducing the resin into the outer side wall plate preform, after glue injection is finished, heating the temperature of the drying oven to 140 ℃, keeping the temperature for 3 hours, heating the temperature of the drying oven to 170 ℃, keeping the temperature for 2 hours, cooling a product along with the furnace, and polishing and cleaning the surface after demolding to obtain the outer side wall plate. The glass fiber felt is in the form of chopped strand mat; the resin selected for use in this step is EH301 epoxy resin. The prefabricated body fiber of the outer side wall plate is quartz fiber.

And step 9: and brushing three-proofing paint on the surface of the cylindrical prefabricated part with the prepared outer side wall plate to form an outer coating.

Example 2

The embodiment discloses a composite material cylindrical part, which is prepared by the method for molding the composite material cylindrical part.

As shown in fig. 1, the heat insulation layer 1, the first transition buffer structure 8 fixedly connected to the outer wall of the heat insulation layer 1, the inner side wall plate 3 fixedly connected to the outer wall of the first transition buffer structure 8, the radial filling structure 4 fixed to the outer wall of the inner side wall plate 3, and the outer side wall plate 5 fixedly connected to the outer wall of the radial filling structure 4 are sequentially arranged from inside to outside.

Fig. 8 shows the appearance, visible, of a cylindrical piece, the external coating 7 being provided with an external coating body 701 and a raised annular projection 702; a cross-sectional view 9a is obtained by cutting a section A1-A1 along the centerline of the annular protrusion 702; section A2-A2 is cut at any point along the exterior coating body 701 to provide a cross-sectional view 9b.

As shown in fig. 9a or 9b, the cylindrical article is further provided with: and the axial support structures 2 are positioned in the radial filling structure 4 and fixed on the outer wall of the inner

side wall plate

3, and 2 axial support structures 2 are arranged and distributed at intervals in the radial direction of the cylindrical part.

As shown in fig. 9a, the cylindrical article is further provided with: the radial support structure 6 is fixed on the outer wall of the radial filling structure 4, and the axial support structure 2 penetrates through the radial support structure 6; the radial support structures 6 are provided with 4 and are distributed at intervals in the axial direction of the cylindrical part; the axial support structure 2 is located inside the radial filling structure 4, and the outside is connected with the outer side wall plate 5, and the outer side wall plate 5 is fixedly connected with the rest side surface of the radial support structure 6.

The inner fillable structure 202 inside the axial support structure 2 is surrounded by an outer reinforcing structure 203; each axial support structure 2 is provided with three fixedly connected circumferentially arranged identical units, each unit being provided with one inner fillable structure 202.

In fig. 9a or 9B, a cross-sectional view 10B, taken along the axial direction B2-B2 in the center of either axial support structure 2; fig. 10a, a cross-sectional view of a section B1-B1, taken at any position of the non-axial support structure 2.

As shown in fig. 10a, there are sequentially arranged from inside to outside: the heat insulation layer comprises an anti-heat insulation layer 1, an inner side wall plate 3, an axial support structure 2, a radial filling structure 4, an outer side wall plate 5 and an outer coating 7; the radial support structures 6 are axially spaced apart between the radial filling structure 4 and the outer sidewall plate 5.

As shown in fig. 10b, there are sequentially arranged from inside to outside: the heat insulation layer 1, the inner side wall plate 3, the axial support structure 2, the outer side wall plate 5 and the outer coating 7; the radial support structures 6 are axially spaced apart between the radial filling structure 4 and the outer sidewall plate 5.

Further, as shown in fig. 7, the first transition buffer structure 8 includes a first rigid connection layer 801, a first flexible support layer 802, and a second rigid connection layer 803 that are sequentially distributed from a high temperature region to a low temperature region; first rigid connection layer 801, first malleable support layer 802, and second rigid connection layer 803 are joined by an adhesive.

As shown in fig. 10a or fig. 10b, a second transition buffer structure 10 is provided between the outer sidewall plate 5 and the radial support structure 6 or the radial filling structure 4. As shown in fig. 15, the second transition buffer structure 10 includes a third rigid connection layer 1001, a second flexible support layer 1002, and a fourth rigid connection layer 1003, which are sequentially distributed from a high temperature region to a low temperature region; the third rigid connection layer 1001, the second malleable support layer 1002, and the fourth rigid connection layer 1003 are connected by an adhesive. Wherein the third rigid connecting layer 1001 is fixedly connected with the outer wall of the radial support structure 6 or the radial filling structure 4, and the fourth rigid connecting layer 1003 is fixedly connected with the inner wall of the outer sidewall plate 5.

First rigid connecting layer 801, second rigid connecting layer 803, third rigid connecting layer 1001 and fourth rigid connecting layer 1003 may be glass fiber mats; selecting a glass fiber mat with the fiber length of 15mm and better flow guiding effect from the glass fiber mats of the third rigid connecting layer 1001 and the fourth rigid connecting layer 1003; the first rigid connecting layer 801 and the second rigid connecting layer 803 are glass fiber felts with the fiber length of 10mm; chopped strands are selected as the glass fiber mats.

The first flexible support layer 802 and the second flexible support layer 1002 can be made of glass fiber cloth; the cloth is composed of grain cloth, twill cloth, and plain cloth, preferably twill cloth with good shear stretch resistance, preferably 190g/cm ³ Twill cloth.

The adhesive comprises: high-temperature-resistant epoxy glue powder, a high-temperature-resistant toughening agent and a high-temperature-resistant diluent; the high-temperature-resistant epoxy glue powder can be EH301 epoxy resin; the dosage and mass ratio of the high temperature resistant epoxy glue powder, the high temperature resistant toughening agent and the high temperature resistant diluent is as follows: 1:0.3:0.05, the high-temperature resistant toughening agent is a common alicyclic amine toughening agent, and the high-temperature resistant diluent is micromolecule alicyclic epoxy.

Preferably, the outer side wall panel 5 has a coefficient of expansion of 10.5 x 10 ^-6 m/DEG C, the coefficient of expansion of the material of the radial support structure 6 or the radial filling structure 4 is not more than 40 multiplied by 10 ^-6 m/DEG C; the thermal insulation layer 1 has an expansion coefficient of 0.15 x 10 ^-6 m/DEG C, and the coefficient of expansion of the material of the inner side wall plate 3 is 7.5 multiplied by 10 ^-6 m/℃。

The matrix resin adopted by the heat-proof and insulation layer 1 is hybrid phenolic resin PF-45; the heat-proof layer adopts carbon fiber as reinforcing fiber. The heat-proof layer adopts a reinforcing material in the form of fabric laminated needling.

The radial filling structure 4, the radial supporting structure 6 and the internal filling structure 202 are made of high-temperature-resistant PEI (polyetherimide) foam sold in the market, and the porosity is 60%; the resin used for each part is shown in Table 1.

The heat conductivity coefficient of the prepared heat-proof and insulating layer 1 is tested by GB/T3139-2005 'test method for heat conductivity coefficient of fiber reinforced plastics'.

GB/T1450.1-2005 'test method for shearing strength between fiber reinforced plastic layers' is adopted to test the shearing strength of the inner side wall and the outer side wall, and the specific application is shown in Table 2.

Comparative example 1

The embodiment discloses a method for forming a composite material cylindrical part, which is the same as that of embodiment 1 except that a hybrid phenolic resin PF-45 is changed into EH301 epoxy resin in comparison with the heat-proof and insulation layer resin in embodiment 1, and specific application thereof is shown in Table 1.

Comparative example 2

The embodiment discloses a method for forming a composite material cylindrical part, which is characterized in that a connection structure of an inner side wall and an anti-heat insulation layer in embodiment 1 is changed from a structure of glass fiber mat, glass fiber cloth and glass fiber mat into a structure of glass fiber mat and glass fiber mat, and the rest is the same as that in embodiment 1, and the specific application is shown in table 1.

Comparative example 3

The embodiment discloses a method for forming a composite material cylindrical part, which is the same as that of embodiment 1 except that no conformal rubber is arranged at the round corners of an outer side wall plate and a radial support structure during the forming processing of the outer side wall plate in embodiment 1, and the specific application is shown in table 1.

TABLE 1

TABLE 2

Experimental group	Thermal conductivity/W/(mK)	Inner side wall shear strength/MPa	Shear strength/MPa of outer sidewall
				Example 1	0.066	60	70
Comparative example 1	0.078	-	-
				Comparative example 2	-	55	60

The thermal insulation layer in embodiment 1 of the invention adopts novel IPC resin, the surface can be ceramic at high temperature, the hardness is hard, and the thermal insulation layer has a uniform nano-pore structure and good thermal insulation performance; compared with the high-temperature resistant resin in the prior art, the heat insulation performance is greatly improved, and compared with the comparative example 1, the heat conductivity is reduced to 0.066W/(mK) from 0.078W/(mK), and is reduced by 15.4%.

Compared with the shear strength of the inner/outer side walls of the comparative example 2 without glass fiber cloth, the shear strength of the inner side wall is improved to 60MPa from 55MPa, the shear strength of the outer side wall is improved to 70MPa from 60MPa, and the shear strength is respectively improved by 9.09% and 16.6%.

Meanwhile, as can be seen from comparison between fig. 11 and fig. 12, after the connection part of the inner side wall plate and the heat-insulating prevention plate in example 1 is used for 1000 times by launching, the phenomena of obvious cracking and stress peeling still do not occur; whereas the inner side wall panel and heat-insulating panel joint of comparative example 2 exhibited significant cracking under the same conditions (as indicated by the circled area in fig. 12). The glass fiber cloth layer can generate certain creep deformation when being subjected to external force; the flexible structure of the glass fiber cloth greatly improves the stress difference and cracking caused by different expansion rates of the foam and the outer side wall plate when the temperature changes, and a good stress buffer layer is integrally formed; and the glass fiber felts close to the radial filling structure and the outer side wall plate are respectively and fixedly connected tightly, so that the defect that the glass fiber cloth body is not strong in strength and poor in anti-shearing capability is effectively overcome.

Meanwhile, as can be seen from the comparison between fig. 13 and fig. 14, the example 1 of the present invention has better appearance and less glue accumulation amount at the round corners of the radial support structure than the comparative example 3 without adding the following rubber because the following rubber is added at the round corners of the outer sidewall plate and the radial support structure.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. A method for forming a composite material cylindrical part is characterized by comprising the following steps:

step 1, dip forming of the heat-proof layer:

step 2, laying a first transition buffer structure:

step 3, vacuum introduction and forming of the inner side wall plate:

preparing a cylindrical workpiece preform with an inner side wall plate fixed outside by taking the outer surface of the first transition buffer structure as a reference surface and adopting a vacuum introduction process;

step 4, forming an axial supporting structure:

step 5, assembling the inner side wall plate and the axial support structure:

step 7, laying a second transition buffer structure:

laying a second transition buffer structure on the outer wall of the cylindrical part prefabricated body with the radial filling structure; the second transition buffer structure comprises a third rigid connection layer (1001), a second flexible support layer (1002) and a fourth rigid connection layer (1003) which are distributed from a high-temperature area to a low-temperature area in sequence;

step 8, forming of an outer side wall plate:

and preparing the outer side wall plate on the outer wall of the second transition buffer structure by adopting a vacuum introduction process.

2. The method of forming a composite tubular article of claim 1,

in the step 1, the dip forming conditions of the thermal insulation layer are as follows: the vacuum degree is more than or equal to 980mbar, the heating temperature is 80-180 ℃, and the forming time is 12-24 h.

3. The method of claim 1, wherein in step 2, the first rigid connecting layer (801) and the second rigid connecting layer (803) are glass fiber mats; the first flexible support layer (802) is glass fiber cloth.

4. The method for forming a composite material tubular article according to claim 1, wherein the step 3 comprises the steps of:

step 3.1: preheating the prefabricated body of the inner side wall plate at 120-130 ℃ after vacuumizing, and gradually increasing the prefabricated body within the range of 600-980 mbar after the negative pressure pumping operation is started;

step 3.3: after the resin is introduced, the mixture is sequentially subjected to heat treatment at 130-150 ℃ and 170-180 ℃ for forming.

5. The method of claim 1, wherein step 4 comprises the steps of:

and 4.2: laying fiber prepreg layer by layer at the position where the internal filling structure is positioned on the panel to prepare reinforcing ribs, performing pre-compaction treatment in a hot compaction mode to prepare a prefabricated body with the reinforcing ribs, and compacting at the temperature of 130-140 ℃ for 15-50 min;

step 4.3: the prefabricated body with the reinforcing ribs is placed in a vacuum bag in a hot pressing tank and is subjected to heat treatment forming at two stages of 130-150 ℃ and 170-180 ℃ in sequence under the pressure of 0.4-0.6 MPa.

6. The method of claim 1, wherein said step 5 comprises the steps of: the axial supporting structure is tightly connected with a cylindrical part prefabricated body of which the outer part is fixed with an inner side wall plate through an adhesive film, and the two-stage heat treatment forming is carried out at 130-150 ℃ and 170-180 ℃ in sequence under the negative pressure environment of 600-980 mbar.

7. The method of forming a composite tubular article of claim 1, wherein said step 6 comprises the steps of:

step 6.2: and (3) carrying out heat treatment molding on the tubular workpiece preform with the radial filling structure and the radial supporting structure sequentially at 130-150 ℃ and 170-180 ℃ in a negative pressure environment of 600-980 mbar.

8. The method for forming a composite tubular article according to claim 1, wherein in step 7, the third rigid connecting layer (1001) and the fourth rigid connecting layer (803) are glass fiber mats; the second flexible supporting layer (1002) is glass fiber cloth.

9. The method of claim 1, wherein in step 8, a release fabric, a release film, a flow guide net and a vacuum bag are sequentially applied to the outer wall of the second transitional buffer structure.

10. The method of claim 9, wherein a conformal rubber is disposed between the vacuum bag and the flow guide net at the rounded corner at the joint of the outer sidewall plate and the fixed end of the radial support structure.