WO2022099707A1

WO2022099707A1 - Core mold for producing hat-shaped reinforcement member

Info

Publication number: WO2022099707A1
Application number: PCT/CN2020/129138
Authority: WO
Inventors: 熊文磊; 苏佳智; 陈萍; 刘卫平; 宁博; 于晶晶; 戚经革; 宋天成; 韩小勇; 闫超; 安慎慎; 王霖; 邱春亮
Original assignee: 中国商用飞机有限责任公司; 上海飞机制造有限公司
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2022-05-19

Abstract

A core mold (20) for producing a hat-shaped reinforcement member. The core mold (20) can be laid in a stringer inner cavity (11) of a stringer (10), such that the stringer (10) and a skin (30) attached to an opening of the stringer inner cavity (11) can be formed into the hat-shaped reinforcement member. The core mold (20) comprises a vacuum bag layer (21) forming a core mold inner cavity (23) and an isolation layer (22) provided outside the outer surface of the vacuum bag layer (21), wherein the vacuum bag layer (21) has a thickness enabling the shape of the core mold (20) to be maintained under a normal temperature state, and the isolation layer (22) is made of an elastic material which is not adhesive to the stringer inner cavity (11). The core mold (20) can maintain the cross-sectional shape without the help of a foreign object, and has enough shape following capability in a length direction. After curing is completed, elasticity of the core mold (20) facilitates demolding thereof.

Description

A core mold for making a hat-shaped reinforcing member

technical field

The invention relates to the field of aircraft structural component molding, and relates to a core mold for manufacturing a hat-shaped reinforcing component.

Background technique

Carbon fiber resin matrix composites have excellent properties. With the continuous improvement of the performance requirements of aircraft-related components, more and more structural components in the aerospace field are made of carbon fiber resin matrix composites. Hat-type (or Ω-type) structural parts are widely used in the aerospace field due to their good stability and high axial load transfer efficiency. In particular, the barrel section of the fuselage of a large passenger aircraft basically adopts a hat-shaped truss reinforced wall panel structure.

Hat-shaped truss reinforced wall panels are generally made by autoclave process. Specifically, an uncured or partially cured stringer and skin are first combined to form a preform with an enclosed space. Among them, according to different situations, the staff can place a core mold capable of filling the closed cavity in the inner cavity of the girder before or after the combination of the girder and the skin. Then, the interior of the closed space is pressurized with a core mold so that both the inner and outer environments of the closed space are in a high-pressure environment, so that the preform is pressurized and heated to solidify the preform into a hat-shaped girder reinforced wall panel.

There are two ways to pressurize the enclosed space of the prefabricated product. One solution is to use the expansion force of the core mold to pressurize the inner cavity of the hat-shaped long stringer; the other solution is to connect the core mold to the autoclave. , the high-pressure air provided by the autoclave can pressurize the inner cavity of the hat-shaped girder.

Existing mandrels are divided into three categories: metal mandrels (including alloy mandrels), rubber mandrels (including solid or hollow rubber mandrels), and tubular vacuum bags.

The metal core mold solidifies and pressurizes the inner cavity of the hat-shaped long stringer through thermal expansion. The advantage of the rubber core mold is that it can ensure the quality of the molding surface of the produced part; Therefore, this type of mandrel is less and less used in actual production.

Solid rubber mandrels also use thermal expansion to pressurize the part. Because the thermal expansion coefficient of solid rubber mandrels is unpredictable and the expansion characteristics change over multiple manufacturing cycles, it is difficult for workers to accurately control the pressure environment that solid rubber mandrels can provide. In addition, the solid rubber mandrel is difficult to extract from the cavity of the cured part.

The hollow rubber core mold is widely used, and its two ends are connected to the high-pressure air environment provided by the autoclave. The advantage of the hollow rubber core mold is that it can ensure uniform curing pressure everywhere in the inner cavity of the part; the disadvantage is that the manufacturing cost of this type of core mold is high, the reliability is poor, the recycling rate is extremely low, and there is damage during use. risk of leakage. For a hat-shaped component with a large size or a complex structure, the inner cavity is more complicated, so this type of core mold is also difficult to extract. In the case of silicone rubber mandrels, it is also possible to contaminate the composite material, adversely affecting bonding and coating.

The tubular vacuum bag is to seal the polymer film into a tubular shape, and achieve the purpose of pressurizing the inner cavity of the hat-shaped long stringer by communicating with an autoclave with high pressure gas. The advantages of this type of mandrel are low cost and uniform curing pressure of the part. The disadvantage is that the vacuum bag is thin, and it is difficult to ensure its own air tightness. It is also prone to damage during the subsequent assembly process with the parts, and vacuum leakage is prone to occur when the parts are cured. In addition, because the tubular vacuum bag is very soft and cannot maintain its shape, in order to better match the inner cavity of the hat-shaped girder, it is usually necessary to support the tubular vacuum bag with external objects and organize the vacuum bag to avoid the vacuum bag being long in the hat-shaped vacuum bag. Bridging or kinking occurs in the truss cavity. In this case, the operation of the mandrel solution for the tubular vacuum bag is complicated and risky, and it is difficult to convert the part manufacturing into an automated operation.

SUMMARY OF THE INVENTION

In view of the above situation of the core mold, one of the objectives of the present invention is to provide a core mold for manufacturing a hat-shaped reinforcing member, which can effectively simplify the part manufacturing process and reduce the part manufacturing cost.

This object is achieved by a device of the present invention in the following form. Wherein, the core mold can be laid in the inner cavity of the girder, so that the girder and the skin attached at the opening of the inner cavity of the girder can be formed into the hat-shaped reinforcing member. The mandrel includes a vacuum bag layer forming an inner cavity of the mandrel and an isolation layer disposed outside the outer surface of the vacuum bag layer, wherein the thickness of the vacuum bag layer is configured to maintain the mandrel at a normal temperature shape, and the insulating layer is made of an elastic material that does not adhere to the inner cavity of the stringer.

The vacuum bag layer is surrounded by an elastic insulating layer, so that the core mold has the elasticity similar to the hollow rubber core mold. The vacuum bag layer has a large thickness, so it can be sufficient to maintain the shape of the mandrel, facilitate the transportation of the mandrel, and the demolding operation after curing. At the same time, the vacuum bag itself also has a certain elastic effect, and its interior can be deformed under pressure, so the core mold can ensure that after the inner cavity of the core mold is pressurized, the outer surface of the core mold can be well attached to the long On the inner surface of the girder, avoid bridging or kinking of the core mold in the inner cavity of the girder.

In addition, thanks to the isolation layer that does not adhere to the inner cavity of the truss, after the curing operation is completed, the vacuum bag layer cooled to the normal temperature shrinks naturally and drives the isolation layer to detach from the inner cavity of the truss naturally. The mold is easily pulled out.

In summary, during use, the core mold of the present application can maintain the cross-sectional shape without the aid of external objects, and at the same time has sufficient conformability in the length direction. The die can undulate or twist with the siding profile.

According to a preferred embodiment of the present invention, the mandrel sidewall of the mandrel is inwardly formed as a concave portion, so that when the inner cavity of the mandrel is in a high-pressure environment, the mandrel sidewall can be deformed and tightly closed Fitted to the inner surface of the hat-shaped reinforcing member. The concave portion allows the core mold to have a certain extension margin during the curing process of the hat-shaped reinforcing member, further avoiding the risk of bridging the core mold.

According to a preferred embodiment of the present invention, the cross section of the core mold is smaller than the cross section of the inner cavity of the long stringer, so that after the core mold is laid in the inner cavity of the long stringer, the outer surface of the core mold and the length A gap can be formed between the inner cavities of the girder.

According to a preferred embodiment of the present invention, the concave portion extends along the length direction of the sidewall of the core mold.

According to a preferred embodiment of the present invention, the concave portions are provided on two opposite sidewalls of the core mold.

According to a preferred embodiment of the present invention, the concave portions are symmetrically arranged on the two core mold side walls of the core mold.

According to a preferred embodiment of the present invention, the concave portion is in an arc-shaped configuration or a angled configuration.

According to a preferred embodiment of the present invention, the vacuum bag layer is made of nylon or thermoplastic elastomer.

According to a preferred embodiment of the present invention, the release layer is made of fluorinated ethylene propylene copolymer or fluorinated ethylene propylene copolymer.

According to a preferred embodiment of the present invention, the wall thickness of the core mold is in the range of 0.1 mm to 0.3 mm.

The present invention also relates to a method for making a hat-shaped reinforcing member using any one of the above-mentioned core molds, the method comprising the following steps:

Lay the skin, and lay the skin on the forming tool;

Lay the long stringers, buckle the long stringers upside down so that the openings of the long stringers face upward, and add adhesive film to the bottom surface of the long stringers for contacting with the skin;

Lay the mandrel, and lay the mandrel in the inner cavity of the girder;

Positioning and gluing, positioning and gluing the long stringer on which the core mold is laid and the skin, so that the long stringer with the core mold is attached to the skin to form a pre-finished hat-shaped reinforcing member together with the skin;

Packaging, bagging and packaging the skin and the long stringer, and sealingly docking the inner cavity of the core mold with the external vacuum bag to pressurize the inner cavity of the core mold, so that the sidewall of the core mold is deformed and tightly adhered to the place. on the inner wall of the inner cavity of the long stringer;

hot-pressing and curing, maintaining the high-pressure environment of the inner cavity of the core mold, and performing hot-pressing curing on the pre-finished product of the hat-shaped reinforcing member;

Demoulding, after the preform of the hat-shaped reinforcing member is solidified, depressurized, and cooled to restore the core mold to its original state, the core mold is withdrawn from the inner cavity.

According to a preferred embodiment of the present invention, the method further includes laying the twist strip between the step of laying the core mold and the positioning and gluing step, wherein in the step of laying the twist strip, the twist strip is laid on the At the opening of the inner cavity of the long stringer, the long stringer does not form a gap between the skins when the opening is located.

On the basis of common knowledge in the field, the above preferred embodiments can be arbitrarily combined to obtain preferred examples of the present invention. Other systems, methods, features and advantages of the present invention will become apparent to those skilled in the art upon reading the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this Summary, be within the scope of the invention, and be protected by the accompanying claims.

Description of drawings

For a better understanding of the above and other objects, features, advantages and functions of the present invention, reference may be made to the preferred embodiments shown in the accompanying drawings. The same reference numbers in the figures refer to the same parts. It will be appreciated by those skilled in the art that the accompanying drawings are intended to schematically illustrate the preferred embodiments of the present invention and not to limit the scope of the invention in any way, and the various components in the drawings are not drawn to scale.

Figure 1 is a schematic diagram of the structure of the truss.

2 is a schematic cross-sectional view of a core mold according to a preferred embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a hat-shaped reinforcing member on which the core mold shown in FIG. 2 will be laid.

FIG. 4 is a schematic cross-sectional view of FIG. 3 .

FIGS. 5 and 6 are schematic cross-sectional views of the hat-shaped reinforcing member on which other alternative mandrels are laid, in the cross-sectional direction of FIG. 4 .

Figures 7 and 8 are schematic cross-sectional views of the girder in the step of laying the mandrel, wherein different forms of mandrels are laid in the inner cavity of the girder in Figures 7 and 8 .

Figure 9 shows a schematic diagram of the skin at the step of laying the skin.

FIG. 10 shows a schematic structural diagram of the packaged aircraft panel.

Detailed ways

Next, the inventive concept of the present invention will be described in detail with reference to the accompanying drawings. What is described here is only the preferred embodiments of the present invention, and those skilled in the art can think of other ways to implement the present invention on the basis of the preferred embodiments, and the other ways also fall within the scope of the present invention. In the following detailed description, directional terms such as "upper", "lower", "inner", "outer", "vertical" and "horizontal" are used with reference to the directions described in the drawings. Components of embodiments of the invention may be oriented in a variety of different orientations, and directional terminology is used for purposes of illustration and not limitation.

For ease of illustration, Figure 1 shows the stringer 10 with its opening facing upwards. The stringer 10 shown in FIG. 1 is used to form a hat-shaped reinforcement member according to the present disclosure. The stringer 10 is a hat-shaped stringer 10 having a substantially "Ω" shape. The plate of the girder 10 defines the girder inner cavity 11 for placing the core mold 20 of the present disclosure and the girder bottom edge 12 extending from the opening of the girder inner cavity 11 to both sides.

In the example of FIG. 1 , the girder inner cavity 11 is formed in the shape of an equilateral trapezoid with an open base.

Referring to FIG. 2 , a mandrel 20 for mating with the stringer 10 of FIG. 1 is shown. The mandrel 20 includes a vacuum bag layer 21 forming an inner cavity 23 of the mandrel and an isolation layer 22 disposed outside the outer surface of the vacuum bag layer 21 , wherein the isolation layer 22 is made of an elastic material that does not adhere to the long stringer inner cavity 11 production.

Optionally, the vacuum bag layer 21 has a larger thickness, so that the vacuum bag layer 21 can maintain the shape of the core mold 20 at normal temperature. The vacuum bag layer 21 is made of nylon or thermoplastic elastomer (TPE), which has certain elasticity. The wall thickness of the vacuum bag layer 21 is preferably set to be not less than 0.075mm, such as 0.08mm, 0.2mm, etc., and most preferably, the wall thickness is set to 0.15mm. Compared with the tubular vacuum bag in the prior art, the vacuum bag layer 21 according to the present disclosure has a larger thickness, and thus has a certain rigidity, so that the inside of the vacuum bag layer 21 can maintain its shape without any additional support. .

The isolation layer 22 is made of fluorinated ethylene propylene copolymer (FEP) or fluorinated ethylene propylene copolymer (ETFE). This material may allow the core mold 20 to be easily released from the inner cavity of the hat-shaped reinforcing member without additional treatment of its surface, thereby facilitating the release of the core mold 20 .

According to the present invention, the wall thickness of the insulating layer 22 has a smaller thickness (lower than the wall thickness of the vacuum bag layer 21). Preferably, the wall thickness of the isolation layer 22 is dimensioned such that the overall wall thickness of the mandrel 20 is in the range of 0.025 mm to 0.05 mm. Advantageously, within this range of wall thickness dimensions, the mandrel 20 can retain a suitable stiffness. During use, the core mold 20 can maintain the cross-sectional shape without the aid of external objects, and at the same time has sufficient conformability in the length direction. When molding a hat-shaped reinforcing member with varying thickness or curvature, the core mold 20 can be undulated or twisted with the inner cavity surface of the hat-shaped reinforcing member, so as to facilitate the molding of the hat-shaped reinforcing member and remove the cap-shaped reinforcing member from the hat-shaped reinforcing member after curing. The reinforcing member is withdrawn from the lumen.

The vacuum bag layer 20 of the core mold 20 and the insulating layer 22 may be bonded by a resin-based adhesive. The adhesive resin layer between the vacuum bag layer 20 and the isolation layer 22 has a small thickness, which can avoid affecting the original performance of the vacuum bag layer 20 and the isolation layer 22 to the greatest extent.

According to the present disclosure, the tensile elongation and tensile strength of the vacuum bag layer 20 are set at higher levels. Specifically, the tensile elongation is set to be not less than 400%, and the tensile strength is set to be not less than 50MPa or more, thereby effectively ensuring the strength of the core mold 20 and not easily damaged during use.

Through the above arrangement, the core mold 20 can combine the performance advantages of the vacuum bag layers 21 and the isolation layers 22 to ensure that the core mold 20 is easy to have appropriate supporting strength and good elastic deformation ability.

The cross section of the core mold 20 should be smaller than the cross section of the inner cavity 11 of the girder. After the core mold 20 is placed in the girder inner cavity 11 , there is still a little gap D between the core mold 20 and the girder inner cavity 11 as shown in FIG. 4 . The gap D between the core mold 20 and the stringer cavity 11 allows the core mold cavity 23 to expand after being pressurized.

Advantageously, the

mandrel side walls

22A, 22B of the mandrel 20 are formed as recesses 24 inwardly. When the inner cavity 23 of the core mold is in a high pressure environment, the

side walls

22A and 22B of the core mold can be deformed to closely fit the inner surface of the hat-shaped reinforcing member. The concave portion 24 allows the core mold 20 to have a certain extension margin during the curing process of the hat-shaped reinforcing member, which further avoids the risk of bridging the core mold 20 .

In some preferred embodiments, the shape of the recesses 24 on the

sidewalls

22A and 22B of the core mold should ensure that the perimeter of the cross section of the core mold 20 is not less than the perimeter of the corresponding inner cavity section of the hat-shaped reinforcing member.

Preferably, as shown in FIG. 3 , the recesses 24 on the

sidewalls

22A and 22B of the core mold extend along the longitudinal direction of the

sidewalls

22A and 22B of the core mold to form continuous strip-shaped recesses 24 . The recessed portion 24 shown in FIG. 3 is a linear strip-shaped recessed portion 24. In fact, it can be replaced with other shapes such as wave-shaped recessed portions that generally extend along the length direction of the

mandrel side walls

22A, 22B.

Referring to the schematic cross-sectional view of the hat-shaped reinforcing member on which the mandrel 20 is laid as shown in FIG. 4 , the recesses 24 are provided on the two opposite

mandrel side walls

22A, 22B of the mandrel 20 , and preferably, the recesses 24 are arranged symmetrically to each other on the two core

mold side walls

22A, 22B of the core mold 20 .

The concave portions 24 of the

sidewalls

22A and 22B of the mandrel can optionally be arranged in an arc-shaped configuration as shown in FIGS. 2 and 4 , an arc-shaped configuration 24A as shown in FIG. The centerline of the arcuate configuration of Figures 2-5 is preferably perpendicular to the plane of the sidewall of the girder on the corresponding side. After the high-pressure gas is injected into the cavity 23 of the core mold, the sidewalls on both sides (the first core mold sidewall 22A) forming the

concave parts

24, 24A, and 24B can be squeezed by the high-pressure gas, so that the side walls adjacent to the first core mold sidewall 22A can be squeezed by the high-pressure gas. The side wall (the second core mold side wall 22B) faces the inner surface of the long stringer cavity 11 and moves along the side wall of the long stringer 10 so that the upper surface of the core mold 20 is fitted to the top of the long stringer 10 and the lower surface is fitted to the top of the long stringer 10 Skin 30.

Preferably, the concave portion adopts the concave portion 24 in the form of a bell mouth as shown in FIGS. 2 and 4 , that is, the concave portion 24 that tapers and smoothly transitions from the opening to the bottom. Referring to FIG. 2 , after the mandrel 20 is laid in the inner cavity 11 of the girder, the first mandrel sidewall 22A located on the upper side will more quickly and evenly connect the second mandrel sidewall 22B on the upper side and the upper part of the mandrel 20 . The surface is extruded to the upper surface of the inner cavity 11 of the long stringer, and the lower side wall 22A of the first core mold pushes the second side wall 22B of the lower side and the lower surface of the core mold 20 to the upper surface of the skin 30 .

Optionally, the corner portion 25 of the core mold 20 toward the bottom of the skin 30 may be provided in the form of a sharp angle as shown in FIGS. 4-7 , or the form of an arc as shown in FIG. 5 .

In the following, the forming process of the hat-shaped reinforcing member is described with reference to the accompanying drawings by taking the forming of the fuselage panel of the aircraft as an example. The forming process of the hat-shaped reinforcing member can be carried out according to the following steps:

1. Laying the skin 30: As shown in the figure, the skin 30 is laid on the forming tool 50 in a fit manner. For an aircraft fuselage, the surface on which the skin 30 is laid on the forming tool 50 is generally arc-shaped. The skin 30 may be laid by conventional wire-laying equipment. The skin 30 in this step is an uncured material, which has flexible properties.

2. Lay the long stringer 10, invert the long stringer 10 so that its opening faces upwards as shown in Figure 1, and add an adhesive film to the bottom surface of the long stringer 10 for contact with the skin 30 (that is, the surface of the bottom edge 12 of the long stringer). . It should be noted that the long stringer 10 in this step has undergone curing treatment in advance, which has strong structural strength.

3. Lay the core mold 20, and lay the core mold 20 in the girder inner cavity 11 of the girder 10 shown in FIG. 1 with the opening facing upward. The long stringer 10 and the core mold 20 are shown in FIG. 7 at this time, and there is a slight gap between them. The laid mandrels 20 are longer in length than the corresponding stringers 10 . After the mandrel 20 is laid, its two ends are exposed from both ends of the long stringer 10 .

Generally, as shown in FIG. 10 , a single piece of skin 30 is provided with a plurality of long stringers 10 .

4. Positioning and gluing, positioning and gluing the long stringer 10 on which the core mold 20 is laid and the skin 30, so that the long stringer 10 on which the core mold 20 is laid is attached to the skin 30 and enters the state shown in FIGS. 4 and 10 . It can be understood that the girder 10 and the skin 30 together form the pre-product of the hat-shaped reinforcing member at this time.

5. Packaging, bagging and packaging the skin 30 and the long stringer 10, and sealingly docking the core mold cavity 23 with an external vacuum bag (not shown) to pressurize the core mold cavity 23, so that the core mold cavity 23 is sealed. The

mold side walls

22A and 22B are deformed to closely fit on the inner wall of the girder cavity 11 . The external vacuum bag can be sealed and connected by the portion of the mandrel 20 exposed from the girder 10 as shown in FIG. 3 . After bagging and packaging, a closed space is formed between the inner cavity 23 of the core mold and the vacuum bag.

6. Hot pressing and curing, maintaining the high pressure environment of the inner cavity 23 of the core mold, and performing hot pressing and curing on the pre-finished product of the hat-shaped reinforcing member. In the autoclave curing step, the encapsulated fuselage panels are placed in an autoclave for curing.

7. Demoulding, after the pre-product of the hat-shaped reinforcing member is solidified, depressurized, and cooled to restore the core mold 20 to its original state, the core mold 20 is pulled out from the inner cavity. Since the core mold 20 of the present invention has a certain elasticity, when the high-pressure air in the core mold cavity 23 is released, the core mold 20 will naturally return to its original state, and a gap will appear again between the core mold 20 and the girder cavity 11 . The elasticity of the core mold 20 itself and the gap between the core mold 20 and the girder inner cavity 11 make it possible for workers to not damage the hat-shaped reinforcing member when pulling the core mold 20 away from the girder inner cavity 11 .

When the corner portion 25 of the core mold 20 toward the bottom of the skin 30 is in the form of an arc, it is understood that a small space will be created where the skin 30, the stringer 10 and the core mold 20 intersect each other. To this end, referring to FIG. 8 , after the core mold 20 is laid in the inner cavity 11 of the girder, the twister bars 40 are laid at the opening of the inner cavity 11 of the girder. The twister bar 40 can completely fill the above-mentioned small space, so as to avoid the formation of a gap between the opening of the stringer 10 between the skins 30 .

The protection scope of the present invention is limited only by the claims. Those skilled in the art, having the benefit of the teachings of the present invention, will readily recognize that alternative structures to the structures disclosed herein are possible alternative embodiments, and that the disclosed embodiments may be combined to create new embodiments. , which also fall within the scope of the appended claims.

Description of reference numbers:

Stringer: 10.

Long stringer cavity: 11.

Bottom edge of stringer: 12.

Mandrel: 20.

Vacuum bag layers: 21.

Isolation Layer: 22.

Mandrel cavity: 23.

Recesses: 24, 24A, 24B.

First mandrel sidewall: 22A.

Second mandrel sidewall: 22B.

Corner parts: 25.

Skin: 30.

Twist strips: 40.

Forming tooling: 50.

Claims

A core mold for making a hat-shaped reinforcing member, the core mold can be laid in the inner cavity of the long stringer, so that the long stringer and the skin attached to the opening of the inner cavity of the long stringer can be formed The hat-shaped reinforcing member is characterized in that:

The mandrel includes a vacuum bag layer forming an inner cavity of the mandrel and an insulating layer disposed outside the outer surface of the vacuum bag layer, wherein the thickness of the vacuum bag layer is configured to maintain the mandrel at a normal temperature shape, and the isolation layer is made of an elastic material that does not adhere to the inner cavity of the long stringer.
The mandrel according to claim 1, wherein the mandrel sidewall of the mandrel is inwardly formed as a recess, so that when the inner cavity of the mandrel is in a high pressure environment, the mandrel sidewall can be It is deformed to closely fit the inner surface of the hat-shaped reinforcing member.
The core mold according to claim 2, wherein the cross section of the core mold is smaller than the cross section of the inner cavity of the long stringer, so that when the core mold is laid in the inner cavity of the long stringer, the A gap can be formed between the outer surface and the inner cavity of the stringer.
The core mold according to claim 2, wherein the concave portion extends along the length direction of the side wall of the core mold.
The core mold according to claim 4, wherein the concave portions are provided on two opposite core mold side walls of the core mold.
The core mold according to claim 5, wherein the concave portions are symmetrically arranged on two core mold side walls of the core mold.
The mandrel according to claim 4, wherein the concave portion is in an arc-shaped configuration or a angled configuration.
The mandrel according to any one of claims 1-7, wherein the vacuum bag layer is made of nylon or thermoplastic elastomer.
The mandrel of claim 8, wherein the isolation layer is made of fluorinated ethylene propylene copolymer or fluorinated ethylene propylene copolymer.
The mandrel according to claim 9, wherein the wall thickness of the mandrel is in the range of 0.1 mm to 0.3 mm.
A method for making a hat-shaped reinforcing member using the core mold according to any one of claims 1-10, wherein the method comprises the following steps:

Lay the skin, and lay the skin on the forming tool;

Lay the long stringers, buckle the long stringers upside down so that the openings of the long stringers face upwards, and add adhesive film to the bottom surface of the long stringers for contacting with the skin;

Lay the mandrel, and lay the mandrel in the inner cavity of the girder;

Positioning and gluing, positioning and gluing the long stringer and the skin on which the core mold is laid, so that the long stringer with the core mold is attached to the skin to form a pre-finished hat-shaped reinforcing member together with the skin;

Packaging, bagging and packaging the skin and the long stringer, and sealingly docking the inner cavity of the core mold with the external vacuum bag to pressurize the inner cavity of the core mold, so that the sidewall of the core mold is deformed and tightly adhered to the place. on the inner wall of the inner cavity of the long stringer;

Hot pressing and curing, maintaining the high-pressure environment of the inner cavity of the core mold, and performing hot pressing and curing on the pre-finished product of the hat-shaped reinforcing member;

Demoulding, after the preform of the hat-shaped reinforcing member is solidified, depressurized, and cooled to restore the core mold to its original state, the core mold is withdrawn from the inner cavity.
12. The method of claim 11, wherein the method further comprises laying the twister strip between the step of laying the mandrel and the positioning gluing step, wherein in the step of laying the twister strip, the twister strip is laid At the opening of the stringer inner cavity, the stringer does not form a gap between the skins at the opening.