JPH0740895A - Tension fitting of composite material - Google Patents

Abstract

PURPOSE:To realize highly strong tension fitting by which inter-layer shearing strength can be increased and local stress concentration is hardly caused. CONSTITUTION:Tension fitting is formed 6f a horseshoe-shaped fitting body 8 formed by layering ply sheets in which fibers are oriented in the circumferential direction, a half column shape patch 4 arranged inside of an end pat part 1 to form the fitting body 8 and fastener bolts 5 to fix the fitting body 8 to a lower side installing plate 14 by passing penetratingly through side plates 2 to form the fitting body 8. Thereby, highly strong fitting by which inter-layer shearing strength is increased and stress concentration on the end pat part 1 or the respective corner parts or the like can be removed and with which tension bolts 3 can be supported reliably, can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced composite material tension fitting applied to structural members such as aircraft and space equipment.

[0002]

2. Description of the Related Art A conventional composite tension fitting applied to a wing fuselage joint of an aircraft is shown in FIG.
As shown in (a), the ply sheet 01 is laminated in the Z direction from the bottom plate, and heat is applied to the ply sheet 01 to cure the ply sheet 01, and as shown in FIG. 2 (b), it is formed by the end pad part 02, the side plate 03, and the bottom plate 04. Had a three-dimensional structure. A tension bolt is inserted in the hole 05.

Such a fitting has a weak interlayer strength because there is no reinforcing fiber between the ply sheets 01, and
Since the end pad part 02 is a flat plate, the end pad part 0
Excessive bending stress and shearing stress are generated at the joint 06 between 2 and the side plate 03, and further, excessive bending and shearing stress are generated at the end pad part 02 and the joint part 07 between the side plate 03 and the bottom plate 04.

[0004]

In the conventional composite tension fitting, as described above, since there is no reinforcing fiber between the layers of the ply sheet, and the shear strength of the interlaminar resin alone is used to transfer the load, the strength is It was low.

Further, since the end pad is a flat plate,
Excessive bending stress and shear stress were generated at the joint between the end pad and the side plate, and the strength was low. Further, excessive bending and shear stress are generated in the joints between the end pad part, the side plates, and the bottom plate, and it is impossible to withstand a large load. The present invention is intended to solve the above problems.

[0006]

The composite tension fitting of the present invention is a horseshoe-shaped fitting body in which ply sheets in which circumferential fibers are oriented are laminated to form a round end pad portion and side plates. , A semi-cylindrical pad provided inside the end pad portion forming the fitting body and through which the tension bolt penetrates together with the end pad portion, and the side plate forming the fitting body is penetrated to the lower side of the fitting body. It features a fastener bolt that is fixed to the mounting plate.

[0007]

In the present invention, since the fitting body is fixed to the lower mounting plate by passing the fastener bolt through the side plate, the interlayer shear strength between the ply sheets is reinforced by the cutting strength of the bolt.

Further, since the pad is disposed inside the end pad, and the head of the tension bolt contacts the pad,
The load from the tension bolt disperses and the compressive stress and interlaminar shear stress are reduced.

Further, since the end pad portion has a round shape and the fibers in the circumferential direction are oriented, the stress from the side plate in the fiber direction can be smoothly converted without concentrating the load from the backing plate.

The bottom plate arranged in the conventional apparatus is not provided in the present invention, and accordingly, the bending stress and the shear stress in the joint between the bottom plate and the end pad and the joint between the bottom plate and the side plate are eliminated. Prevent occurrence.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. In this embodiment shown in FIG. 1, in FIG. 1 (c), (d),
Ply sheet 7a for one prepreg in which circumferential fibers 6a, radial fibers 6b, + 45 ° oblique fibers 6c, and −45 ° oblique fibers 6d shown in (e) and (f) are respectively oriented. , 7b, 7c, 7d are laminated as shown in FIG. 1 (g) to form a round-shaped end pad portion 1 and a side plate 2, and a horseshoe-shaped fitting body 8 and an end pad forming the fitting body 8 are formed. The semi-cylindrical pad 4 provided inside the portion 1 and the side plate 2 forming the fitting body 8 are passed through the same 1 (b).
As shown in FIG. 6, six fastener bolts 5 for fixing the fitting body 8 to the lower mounting plate 14 are provided.

A pad up portion 9 is provided on the outer surface of the end pad portion 1 of the fitting body 8 as shown in FIG. 1 (h), and a mounting surface 10 is formed flat. In addition, as shown in FIG.
As shown in (h), a hole 11 for the tension bolt 3 that penetrates the fitting body 8 and the pad 4 is provided. Further, the side plates 2 forming the fitting body 8 have a constant opening angle 12 as shown in FIG. 1 (c).

In the composite material tension fitting of this embodiment, since the fitting body 8 is formed of the end pad portion 1 and the side plate 2 and there is no bottom plate, the bottom plate and the end pad portion 1 which are the damaged parts in the conventional apparatus, and No bending stress or shear stress is generated at the joint between the bottom plate and the side plate 2, and no damage occurs. This improves the strength of the fitting. Moreover, the work becomes easy.

Further, since there is no bottom plate, the height of the entire fitting can be kept low according to the size of the head of the tension bolt 3, and the offset moment 14 that causes a large bending stress in the composite tension fitting is reduced. However, the strength can be improved.

The end pad portion 1 of the fitting body 8 has a round shape in which circumferential fibers 6a, radial fibers 6b, and oblique fibers 6c and 6d are oriented. In particular, the circumferential fibers 6a are , The load from the pad 4 is smoothly converted into the circumferential fiber stress of the side plate 2 without being concentrated on the joint between the end pad 1 and the side plate 2.

The area around the tension bolt hole 11 is
Since the pad-up portion 6 is provided so that the mounting surface 10 of the composite material fitting becomes flat, it is possible to reinforce the decrease in strength due to the tension bolt holes 11 and to withstand a compressive load.

Further, a pad 4 is provided inside the end pad 1.
Since the head of the tension bolt 3 is in contact with the pad 4, the pad 4 disperses the load from the tension bolt 3 and reduces the compressive stress and the interlayer shear stress caused by the distribution of the compressive stress.

Side plates 2 on both sides of the fitting body 8
Are not parallel and have an opening angle 12 of 3 ° to 50 °, stress concentration at the contact point with the pad 4 can be avoided, and the fastener bolt 5 penetrates the side plate 2,
The interlayer shear strength between the ply sheets 7a, 7b, 7c, 7d is reinforced by the shear strength of the bolt.

[0019]

The composite tension fitting of the present invention has a horseshoe-shaped fitting body formed by laminating ply sheets in which fibers in the circumferential direction are oriented, and the inside of the end pad portion forming the fitting body. To the end pads and corners by being formed by a semi-cylindrical pad provided on the and the fastener bolts that penetrate the side plate forming the fitting body and fix the fitting body to the lower mounting plate. It is possible to eliminate the stress concentration and to realize a high-strength fitting that can reliably support the tension bolt.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of the present invention, (a) is a perspective view, (b) is a cross-sectional view, (c), (d), (e), (f).
Is an explanatory view of a ply sheet in which circumferential fibers, radial fibers, + 45 ° oblique fibers, and −45 ° oblique fibers are oriented, respectively. (G) is (c), (d), (e) ，
Explanatory drawing of the state where the ply sheets of (f) were laminated,
(H) is explanatory drawing of a put-up part.

2A and 2B are explanatory diagrams of a conventional device, FIG. 2A is an explanatory diagram of a ply sheet to be laminated, and FIG. 2B is an explanatory diagram of a completed state.

[Explanation of symbols]

 1 End Pad Part 2 Side Plate 3 Tension Bolt 4 Abutment 5 Fastener Bolt 6a, 6b, 6c, 6d Fiber 7a, 7b, 7c, 7d Ply Sheet 8 Fitting Body 9 Put Up Part 10 Mounting Surface 11 Tension Bolt Hole 14 Mounting Plate

Claims (1)

[Claims] 1. A horseshoe-shaped fitting body in which ply sheets in which circumferential fibers are oriented are laminated to form a round end pad portion and side plates, and inside the end pad portion forming the fitting body. It is provided with a semi-cylindrical pad that is provided with the end pad and through which the tension bolt penetrates, and a fastener bolt that penetrates the side plate that forms the fitting body and that fixes the fitting body to the lower mounting plate. And composite material tension fitting.