JPH07102609B2 - Method for molding fiber-reinforced composite material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a fiber-reinforced composite material for producing structural members and the like from the fiber-reinforced composite material.

[0002]

2. Description of the Related Art Structural members such as aircraft and vehicles are desired to have high impact resistance and toughness and be lightweight. or,
In particular, a supersonic aircraft is required to have heat resistance (for example, 185 ° C or higher) that can withstand aerodynamic heating at supersonic speed. Fiber-reinforced composite materials are suitable as primary structural materials used for such purposes. Among them, especially thermoplastic composite materials,
As shown in FIGS. 6 and 7, it has excellent impact resistance and toughness.

Conventionally known methods for molding such a fiber-reinforced composite material are a matched die press molding method, a diaphragm molding method, a pull-through molding method, an autoclave molding method and the like.

However, although the matched die press molding method can obtain a highly accurate molded product, it is not suitable for a large-sized component due to the apparatus, and the jig cost is increased because a double-sided mold is required. The diaphragm molding method has an advantage that a deep-drawn molded product having a complicated shape can be easily obtained, but is not suitable for a large-sized part as described above. The pultrusion molding method can continuously and efficiently form long parts, but has a problem that it cannot cope with changes in cross section and plate thickness. In addition, the autoclave molding method has a large degree of freedom in shape that can be molded and can be used for large parts, but it requires a large temperature and pressure large autoclave device because of long heating and cooling times and poor productivity. There is a problem that the production cost increases because it is necessary to stack the fiber-reinforced composite material layers one by one on top. In particular, in the case of a thermoplastic composite material in which the tackiness and drape property of the material are poor, it is very difficult to stack the materials according to the shape of the molding die.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above problems in the prior art, enables efficient production of large parts with a simple apparatus, and is fiber reinforced that can cope with changes in sectional shape and plate thickness. An object is to provide a method for molding a composite material.

[0006]

In order to solve the above problems, the present invention provides (a) a flat plate-shaped fiber-reinforced thermoplastic composite material laminated in multiple layers with a diaphragm material on the surface of the plate material. Covering so as to project from the
(B) a step of placing the covered material on a molding die for bending into a predetermined shape and heating it to a molding temperature; (c) sandwiching a portion of the diaphragm material protruding from both ends of the composite material. And sequentially applying a force in the direction of bending.

[0007]

The plate material of the fiber-reinforced composite material is obtained by impregnating fibers such as carbon fibers and glass fibers with a resin and laminating the fibers. For this reason, when bending is performed by a method of heating the material and gripping both ends of the material to bend it, the fiber may be cut or the fiber layer may be disturbed to form a strong and high-quality product. There is a problem. According to the present invention, a force is applied in a direction in which the portion of the diaphragm material that projects from both ends of the composite material is clamped and bent, so that the one having the larger curvature of the fiber layer is pulled by the diaphragm material. By receiving the frictional force on the fiber, the fiber layer is stretched and bent according to the curvature of each fiber, so that the fiber is not disturbed by the bending. In addition, since the load for applying a bending moment to the bending part at the end of the mold is applied as a good distributed load near the end of the thermoplastic composite material by the flat surface of the diaphragm material, The diaphragm material is not locally deformed, and the diaphragm material is bent along the curvature of the mold without disturbing the fiber layer.

[0008]

EXAMPLE FIG. 1 is a diagram for explaining a method for molding a fiber-reinforced composite material according to an example. In this molding method, (a) a superplastic sheet 2 (usually an aluminum sheet) as a diaphragm material is used for the surface of a thermoplastic composite flat plate 1 which is an example of a flat plate-shaped fiber-reinforced composite material laminated in multiple layers. A step of covering both ends of the flat plate 1 so as to project from both ends, (b)
A step of placing the covered material on a molding jig 3 which is a molding die for bending it into a predetermined shape and heating it to a molding temperature by heaters 4, 5, 6, 7; and (c) heaters 5, 7 In the direction in which the parts 2a, 2b of the superplastic sheet 2 protruding from both ends of the thermoplastic composite flat plate 1 are clamped by the clamps 8, 9 and bent as indicated by arrows A, B by moving downward. The step of applying force is sequentially included. In this case, when applying a force in the bending direction, it is preferable that the clamps 8 and 9 pull the superplastic sheet 2 in mutually opposite directions.

In the above process, the molding temperature is a temperature at which the fiber-reinforced composite material is softened, and in the thermoplastic composite material, the molding temperature is about 4.
00 ° C, about 80 ° C to 100 ° C for thermosetting composite materials
Is. Further, the superplastic sheet has a property of elongating at high temperature, and by being bent while being stretched, a bending force is applied as a distributed load to the composite material along the side having a large curvature.

FIG. 2 shows a state in which the thermoplastic composite material is finally molded as the channel material 10. Of course, other shapes such as angle materials can be easily formed by using a forming die.

The thermoplastic composite material has a fiber layer, and the curvature of each fiber is different at the bent portion. When such a molding method is used, the fiber is pressed from the outer layer and each fiber follows each curvature. It will not be disturbed by being bent and misaligned between fiber layers. In addition, since no autoclave or hot press is used, the molding time can be shortened at a low device jig cost, and changes in cross-section and plate thickness can be easily accommodated. Cooling is also possible. Further, since the work of laminating the materials one by one along the molding die is not required, the molding cost can be reduced, and as described above, it is possible to easily cope with the molding of the thermoplastic composite material in which the laminating work is difficult. .

As shown in FIGS. 3 to 5, the channel material 10 thus formed, the corner filler 11 and the plate material 12 are combined and joined to form an I-shaped material 13, or a larger plate material 14 is combined. Large structure skin panel 15 (for example, width 1m x length 1.5m)
Is also easy to manufacture.

[0013]

As described above, according to the present invention, since the fiber layer is bent while being stretched, the fibers are not disturbed by bending. In addition, the load for bending without grasping the fiber itself is applied as a good distributed load near the end of the thermoplastic composite material by the flat surface of the diaphragm material, so the part under load of the material is locally The diaphragm material is bent along the curvature of the forming die without being distorted in the fiber layer without any disturbance. Also, since no autoclave or hot press is used, the molding time can be shortened at a low jig cost, and changes in cross-section and plate thickness can be easily accommodated. Furthermore, rapid heating and cooling of the molding jig are possible. Will also be possible. In addition, since it is not necessary to manually bend and stick the fiber layers one by one as in the prior art and then attach the fiber layers to the molding die, the working efficiency is greatly improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method for molding a fiber-reinforced composite material according to an example.

FIG. 2 is an explanatory diagram of a method for molding a fiber-reinforced composite material according to an example, showing a molded state.

FIG. 3 is an explanatory view showing a state where an I-shaped material is manufactured using the molded channel material.

FIG. 4 is a perspective view of the I-shaped member.

FIG. 5 is a perspective view of a skin panel manufactured using the molded channel material.

FIG. 6 is a graph showing a comparison of the compressive strengths of a thermoplastic composite material and a thermosetting composite material after impact loading.

FIG. 7 is a graph showing a comparison of Mode 1 interlaminar fracture toughness values of a thermoplastic composite material and a thermosetting composite material.

[Explanation of symbols]

 1 Thermoplastic composite material (fiber reinforced composite material) 2 Superplastic sheet (diaphragm material) 2a Overhanging portion 2b Overhanging portion 3 Molding jig (molding die)

Claims (1)

[Claims] 1. A step of: (a) covering the surface of a plate-shaped fiber-reinforced thermoplastic composite material laminated in multiple layers with a diaphragm material so that the diaphragm material projects from both ends of the plate material;
(B) a step of placing the covered material on a molding die for bending into a predetermined shape and heating it to a molding temperature; (c) sandwiching a portion of the diaphragm material protruding from both ends of the composite material. And a step of applying a force in the direction of bending.