JPH10278185A - Manufacture of sandwich structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sandwich structure of an arbitrary curved surface shape by molding and curing a skin material for the sandwich structure and bonding and curing the skin material and a core material simultaneously, then laminating a prepreg on a molding jig and a stiffening plate respectively and bagging the prepreg and effecting evacuation. SOLUTION: A fiber-reinforced plastic prepreg 2a which serves as a skin material is laminated on a molding jig, then is bagged and a vacuum is drawn from the bag. Next, a fiber-reinforced plastic prepreg 2b which serves as the skin material for a stiffening plate 6 side is laminated on the inner face of the stiffening plate 6, then is bagged and a vacuum is drawn from the bag. Further, on the fiber-reinforced plastic prepreg 2a which serves as the skin material on the molding jig 1 side, an adhesive 4, a core material 5 and the adhesive 4 are arranged in that order. In addition, the stiffening plate 6 and the fiber-reinforced plastic prepreg 2b which are laminated together and integrated into one piece by drawing a vacuum from the bag are arranged on the adhesive 4. Thereafter, the fiber-reinforced plastic prepregs 2a, 2b are thermally cured with the adhesive 4 through the bagging process and the vacuum drawing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sandwich structure which is composed of a skin material and a core material formed of fiber reinforced plastic and is effective for, for example, a space structure.

[0002]

2. Description of the Related Art For structures requiring light weight, high rigidity and high strength, such as space structures, a sandwich structure having a skin material made of fiber reinforced plastic and a core material made of a honeycomb material is frequently used. I have. FIG. 5 is a schematic cross-sectional view showing a conventional method for manufacturing a sandwich structure using a fiber-reinforced plastic as a skin material. The conventional method for manufacturing a sandwich structure will be described with reference to FIG.

In FIG. 5A, first, a fiber-reinforced plastic prepreg 2 is laminated and formed on a forming jig 1 having a curved surface. Next, after bagging, evacuation and hardening, the skin material 3 is obtained in FIG. This step 2
This is repeated twice to produce two skin materials 3. Next, FIG.
In (c), after forming the surface material 3a on the forming jig side, the adhesive 4, the core material 5, the adhesive 4, and the surface material 3b on the backing plate side on the forming tool 1, bagging and evacuation are performed. I do. Then, by heating and curing the adhesive 4,
A sandwich structure having a desired shape is obtained. Usually, an autoclave molding method is used as a method for molding and curing the skin material 3 and a method for heating and curing the adhesive 4, but other molding methods such as a vacuum molding method are also possible. In FIG. 5C,
Although a backing plate is not shown on the outer (upper) side of the skin material 3b, it is also possible to manufacture using a backing plate.

[0004]

In the conventional method of manufacturing a sandwich structure, the molding and curing of the skin material is performed twice, and the bonding and curing of the skin material and the core material is performed once and the curing process is performed three times in total. This is necessary, and there is a problem that the manufacturing process becomes complicated and the construction period takes too much time.

Further, in the conventional manufacturing method, the skin material on the forming jig side and the skin material on the backing plate side are exactly the same, and the contour shape is obtained by transferring the curved surface of the forming jig. And lacks flexibility and flexibility.
However, in the manufacture of a sandwich structure having an arbitrary curved surface, the skin material on the backing plate side has to be bonded and cured with a different curvature of the curved surface by the thickness of the core material compared to the skin material on the forming jig side. Therefore, it is difficult to make the skin material on the backing plate side along (outside) the core material on an arbitrary curved surface, particularly a curved surface having irregularities or a curved surface having a large curvature. Inconveniences such as poor adhesion with the material were likely to occur. As a result, there is a problem that a sandwich structure having an arbitrary curved surface cannot be obtained.

Also, in a manufacturing method for simultaneously forming and curing the skin material of the sandwich structure and bonding and curing the skin material and the core material, a backing plate is used on the outer side of the skin material opposite to the molding jig. If not, dimples (referred to as dimple-shaped depressions generated in the center of hexagonal cells of the honeycomb core material) are likely to be generated in the skin material on the side opposite to the molding jig due to the pressure during curing and the vacuum pressure. There was a point. The occurrence of dimples causes a decrease in bending rigidity, which is an important property of the sandwich structure, and as a result, there has been a problem that a sandwich structure having an arbitrary curved surface cannot be obtained.

In a manufacturing method for simultaneously forming and curing the skin material of the sandwich structure and bonding and curing the skin material and the core material, a backing plate is used on the outside of the skin material on the side opposite to the molding jig. Even in this case, simply laminating the fiber reinforced plastic prepreg, which forms the skin material on the opposite side to the molding jig, on the outer (upper) side of the core material, results in insufficient adhesion between the layers of the fiber reinforced plastic prepreg. After curing, there was a danger that the interlaminar strength of the skin material which became the fiber-reinforced plastic became low. A decrease in the interlayer strength of the skin material causes a decrease in bending stiffness, bending strength, flatwise tensile strength, and the like, which are important properties as a sandwich structure, and as a result, it is not possible to obtain a sandwich structure having an arbitrary curved surface shape. There was a problem.

Also, in a manufacturing method for simultaneously forming and hardening the skin material of the sandwich structure and bonding and hardening the skin material and the core material, a patch having a characteristic such as a coefficient of linear expansion far from that of the skin material. When using a board,
Due to the difference in the coefficient of linear expansion between the skin material and the caul plate, a difference in thermal deformation occurs between the skin material and the caul plate due to the temperature difference between room temperature and the curing temperature, and the skin material on the caul plate side is wrinkled or broken. There was danger. As a result, there is a problem that a sandwich structure having an arbitrary curved surface cannot be obtained.

Also, in a manufacturing method for simultaneously forming and curing the skin material of the sandwich structure and bonding and curing the skin material and the core material, a contour shape different from the contour shape of the sandwich structure skin material on the backing plate side. In the case of using a backing plate having a backing plate, it is difficult to follow the backing plate along an arbitrary curved surface, particularly a curved surface having irregularities and a curved surface having a large curvature, and wrinkles and breaks of the skin material and the skin material and the core material Inconveniences such as poor adhesion between them were likely to occur. Therefore, there is a problem that a sandwich structure having an arbitrary curved surface cannot be obtained.

[0010]

Means for Solving the Problems In the first invention,
Since it is a manufacturing method that simultaneously forms and cures the skin material of the sandwich structure and adheres and cures the skin material and the core material, only one curing step is required, and the sandwich is manufactured in a short construction period without complicating the production process. A structure can be manufactured.

Further, the fiber reinforced plastic prepreg forming the skin material is a material having high flexibility and flexibility at the time of lamination. According to the manufacturing method of the present invention, the skin material on the backing plate side is formed on the molding jig side. Even if the curvature of the curved surface differs by the thickness of the core material compared to the surface material of the above, the fiber-reinforced plastic prepreg is laminated along the curved surface of the inner surface of the backing plate to form the skin material on the backing plate side It is possible to manufacture a high-performance sandwich structure having an arbitrary curved shape.

Further, by using a backing plate on the outer side of the skin material opposite to the molding jig, the rigidity of the caulking plate causes the pressure at the time of hardening and the vacuum pressure to influence the skin material opposite to the molding jig. The fiber-reinforced plastic prepreg can be suppressed from being pressed and depressed at the center of the honeycomb core material. Therefore, it is possible to manufacture a sandwich structure having an arbitrary curved surface shape without generating dimples on the skin material.

Further, a fiber-reinforced plastic prepreg for forming the skin material on the forming jig side and the backing plate side is laminated on the forming jig and the backing plate with a predetermined fiber orientation and the number of layers, respectively, bagged and vacuumed. By pulling, the adhesion between the layers of the fiber reinforced plastic prepreg can be sufficiently increased. Therefore, it is possible to manufacture a sandwich structure having an arbitrary curved surface shape having a high interlayer strength of the skin material.

Further, in the second invention, by using a backing plate formed of the same type of fiber reinforced plastic prepreg as the skin material, characteristics such as a coefficient of linear expansion can be made uniform between the skin material and the backing plate. It is possible to suppress a shift in thermal deformation between the skin material and the backing plate due to a temperature difference between the room temperature and the curing temperature. Therefore, it is possible to manufacture a sandwich structure having an arbitrary curved surface shape without wrinkling or breaking of the skin material.

Further, in the third invention, an arbitrary curved surface, in particular, a curved surface having irregularities and a curved surface having a large curvature can be obtained by using a backing plate whose contour shape is the same as the contour shape of the skin material on the backing plate side. In this case, the backing plate can be moved along. Therefore, it is possible to manufacture a sandwich structure having an arbitrary curved surface shape without causing problems such as wrinkles and breaks of the skin material and poor adhesion between the skin material and the core material.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 (a), 1 (b) and 1 (c) are schematic cross-sectional views showing steps for manufacturing a sandwich structure according to Embodiment 1 of the present invention. A method for manufacturing a sandwich structure according to the present invention will be described with reference to FIG. First, as shown in FIG. 1A, a fiber reinforced plastic prepreg 2a serving as a skin material on the forming jig side is laminated on a forming jig 1 having irregularities in a predetermined fiber orientation and a predetermined number of layers, bagged, and vacuumed. To pull. Next, in FIG.
A fiber reinforced plastic prepreg 2b as a skin material on the side of the backing plate is laminated on the inner surface with a predetermined fiber orientation and the number of layers, bagged and evacuated. Next, in FIG. 1C, an adhesive 4, a core material 5, and an adhesive 4 are arranged in this order on a fiber-reinforced plastic prepreg 2a serving as a skin material on the molding jig side. Further, in FIG. 1 (b), the backing plate 6 and the fiber reinforced plastic prepreg 2b which are laminated and evacuated and integrated are arranged. After that, bag it and evacuate it,
By heating and curing the fiber reinforced plastic prepregs 2a and 2b and the adhesive 4 in an autoclave, a sandwich structure having a desired curved shape can be obtained. In this embodiment, the fiber-reinforced plastic prepreg and the adhesive were heated and cured by the autoclave molding method, but other molding methods such as a vacuum molding method are also possible.

Embodiment 2 FIG. 2 (a) to 2 (c) are schematic cross-sectional views illustrating steps for manufacturing a sandwich structure according to Embodiment 2 of the present invention. A method for manufacturing the sandwich structure according to the present invention will be described with reference to FIG.
First, as shown in FIG. 2A, a fiber-reinforced plastic prepreg 2a serving as a skin material on the molding jig side is laminated on the molding jig 1 with a predetermined fiber orientation and the number of layers, bagged, and evacuated. Next, in FIG. 2 (b), a fiber-reinforced plastic prepreg 2b serving as a skin material on the side of the caul plate is provided with a predetermined fiber orientation on the inner surface of the caul plate 6a previously formed of the same type of fiber-reinforced plastic prepreg as the skin material. Laminate in layers, bag and vacuum. Next, in FIG. 2C, an adhesive 4, a core material 5, and an adhesive 4 are arranged in this order on a fiber-reinforced plastic prepreg 2a serving as a skin material on the molding tool side. Further, in FIG. 2B, the backing plate 6a and the fiber reinforced plastic prepreg 2b which are laminated and evacuated and integrated are arranged. Thereafter, bagging and vacuuming are performed, and the fiber-reinforced plastic prepregs 2a and 2b and the adhesive 4 are heated and cured in an autoclave, whereby a sandwich structure having a desired curved surface shape is obtained. In this embodiment, the fiber-reinforced plastic prepreg and the adhesive were heated and cured by the autoclave molding method, but other molding methods such as a vacuum molding method are also possible.

Embodiment 3 3 and 4 are schematic cross-sectional views showing steps for manufacturing a sandwich structure according to Embodiment 3 of the present invention. A method for manufacturing a sandwich structure according to the present invention will be described with reference to FIGS. First, as shown in FIG. 3 (a), a raising jig 1 b having a thickness equal to the thickness of the sandwich structure is placed on the forming jig 1, and a fiber-reinforced plastic prepreg 2 is placed on a predetermined fiber. Lamination is performed with the orientation and the number of layers. Thereafter, bagging and vacuuming are performed, and the fiber-reinforced plastic prepreg 2 is heated and cured in an autoclave, thereby obtaining the same shape as the contour shape of the sandwich structure skin material on the backing plate side as shown in FIG. A contact plate 6b having a contour shape is obtained. In this embodiment, a fiber-reinforced plastic prepreg is laminated on a molding jig for raising,
Although the backing plate is formed by evacuation and heating and curing in an autoclave, the backing plate can be formed by other materials and methods such as stretching of a low thermal expansion alloy plate.

Next, as shown in FIG. 4A, a fiber reinforced plastic prepreg 2a serving as a skin material on the forming jig side is laminated on the forming jig 1 in a predetermined fiber orientation and the number of layers, and bagging is performed. And evacuate. Next, in FIG. 4 (b), a fiber reinforced plastic prepreg 2b as a skin material on the side of the backing plate is laminated on the inner surface of the backing plate 6b obtained in FIG. 3 (b) with a predetermined fiber orientation and number of layers, and bagging is performed. And evacuate. In (c), an adhesive 4, a core material 5, and an adhesive 4 are arranged in this order on a fiber-reinforced plastic prepreg 2a serving as a skin material on the molding jig side. Further, the backing plate 6b and the fiber reinforced plastic prepreg 2b, which are laminated and evacuated as shown in FIG. afterwards,
Bagging, vacuuming, and heating and curing the fiber reinforced plastic prepregs 2a and 2b and the adhesive 4 in an autoclave can obtain a sandwich structure having a desired curved surface shape. In this embodiment, the fiber-reinforced plastic prepreg and the adhesive are heated and cured by the autoclave molding method, but other molding methods such as a vacuum molding method are also possible.

[0020]

According to the first aspect of the present invention, the molding and curing of the skin material of the sandwich structure and the adhesion and bonding of the skin material and the core material are performed.
Since the method is a manufacturing method in which curing is performed simultaneously, only one curing step is required, and the sandwich structure can be manufactured in a short construction period without complicating the manufacturing process. The fiber-reinforced plastic prepreg forming the skin material is a material having high flexibility and flexibility at the time of lamination molding, and the fiber-reinforced plastic prepreg conforms to any curved surface, particularly a curved surface having irregularities and a curved surface having a large curvature. It is possible to stack them together. Therefore, it is easy for the skin material on the side of the backing plate to extend along (outside) the core material, and there are no problems such as wrinkles and breaks of the skin material and poor adhesion between the skin material and the core material.
It is possible to obtain a sandwich structure having an arbitrary curved shape.

Further, since the backing plate is used on the outer side of the skin material opposite to the molding jig, it is hardly affected by pressure and vacuum pressure at the time of curing, and the skin material opposite to the molding jig has wrinkles and dimples. , And a sandwich structure having an arbitrary curved shape having high bending rigidity can be obtained.

Further, by laminating the fiber-reinforced plastic prepreg on the molding jig and the backing plate, bagging each of them and vacuuming them, the adhesion between the layers of the fiber-reinforced plastic prepreg can be sufficiently increased. Therefore, the interlayer strength of the skin material can be increased, and the flexural rigidity and
It is possible to obtain a sandwich structure having an arbitrary curved surface excellent in mechanical properties such as bending strength and flatwise tensile strength.

According to the second aspect of the present invention, by using the backing plate formed of the same kind of fiber-reinforced plastic prepreg as the skin material of the sandwich structure, the skin material has a temperature difference between room temperature and curing temperature. It is possible to prevent the occurrence of a shift in the thermal deformation between the support plate and the contact plate. Therefore, it is possible to obtain a sandwich structure having an arbitrary curved surface shape without wrinkling or breaking of the skin material.

According to the third aspect of the present invention, an arbitrary curved surface, in particular, a curved surface having irregularities and a large curvature is used by using the backing plate whose contour shape is the same as the contour shape of the skin material on the backing plate side. The caul plate can be moved along the curved surface. Therefore, it is possible to obtain a sandwich structure having an arbitrary curved surface shape without causing problems such as wrinkles and breaks of the skin material and poor adhesion between the skin material and the core material.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a manufacturing process according to a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a manufacturing process according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing a manufacturing process according to a third embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view illustrating a manufacturing process of a conventional sandwich structure.

[Description of Signs] 1 Molding tool, 3 skin material, 4 adhesive, 5 core material, 6 backing plate.

Claims (3)

[Claims] 1. A method of manufacturing a sandwich structure using a fiber-reinforced plastic as a skin material, comprising forming and curing a skin material formed of a fiber-reinforced plastic prepreg as an intermediate material, and a core material of the skin material and the sandwich structure. At the same time as bonding and curing, the molding tool is an open mold used only on one side of the sandwich structure, and a patch plate is used on the outside of the skin material of the sandwich structure opposite to the molding tool, A manufacturing method characterized by laminating a fiber reinforced plastic prepreg on a forming jig and a backing plate with a predetermined fiber orientation and a predetermined number of layers, bagging each of them, and evacuating each. 2. A method for manufacturing a sandwich structure using a fiber-reinforced plastic as a skin material, wherein the same type of fiber-reinforced plastic prepreg as the skin material is used for the backing plate. Production method. 3. A method of manufacturing a sandwich structure using a fiber-reinforced plastic as a skin material, wherein the contour of the backing plate is the same as the contour shape of the sandwich structure skin material on the backing plate side. 2. The production method according to 1.