Composite material stringer

Abstract

The utility model discloses a composite material stringer which is fixed on a fuselage wall plate, the stringer is made of carbon fiber reinforced epoxy resin composite materials, the cross section of the stringer is of a cap-shaped structure, the cap-shaped stringer cross section is provided with four corners, and the four corners comprise two lower stringer internal corners and two upper stringer external corners. A plurality of triangular reinforcing ribs are arranged on the inner sides of the two stringer external corners at intervals, no triangular reinforcing ribs are arranged on the inner sides of the two stringer internal corners, and a pre-deformation area is formed between the stringer internal corners and the fuselage wall plate. The triangular reinforcing rib is designed on the inner side of the external corner of the stringer, and the pre-deformation area is formed between the internal corner of the stringer and the fuselage wall plate, so that the bending rigidity of the fuselage wall plate in the width direction can be increased, and the bending deformation of the composite material skin in the width direction is limited in the curing forming process; and the deformation resistance of the fuselage wall plate in the width direction in use is improved.

Description

Technical Field

[0001] This utility model relates to the field of composite material product design, and in particular to a composite material stringer. Background Technology

[0002] To enhance the flexural strength of the carbon fiber reinforced composite fuselage panels, cap-shaped composite stringers will be used for reinforcement. The stringers and skin will be bonded together using a co-bonding process. This involves first curing the stringers, then bonding the cured stringers to the uncured skin for a second curing.

[0003] However, during the curing process of thermosetting composite materials, factors such as the mismatch in the thermal expansion coefficients of the resin and fiber, and the chemical shrinkage of the resin can lead to the accumulation of residual stress inside the material. This causes curing deformation after demolding, further increasing the curvature of the composite panel. This problem seriously affects the dimensional stability and assembly quality of the product. Furthermore, the cap-shaped stringer section has four corners (also called radius corners), including two internal corners and two external corners. The advantage of the cap-shaped stringer is its high design flexibility, allowing for cross-thickness bonding, but its disadvantage is the poor resistance to deformation at the radius corners, making the entire composite panel more prone to deformation in the width direction. Utility Model Content

[0004] The purpose of this utility model is to solve the technical problems existing in the prior art and to provide a composite material stringer.

[0005] To achieve the above objectives, the technical solution provided by this utility model is: a composite material stringer, the stringer being fixed to the fuselage wall panel, the stringer being made of carbon fiber reinforced epoxy resin composite material, the stringer having a hat-shaped cross-section with four corners, including two lower internal corners and two upper external corners, with several triangular reinforcing ribs spaced apart on the inner side of the two external corners, and no triangular reinforcing ribs on the inner side of the two internal corners, and a pre-deformation area formed between the internal corners of the stringer and the fuselage wall panel.

[0006] Preferably, the design angle of the inner corner of the stringer exceeds the standard angle when the bottom surface of the stringer is fully in contact with the fuselage panel, and the design angle of the inner corner of the stringer exceeds the standard angle by 1 to 20°.

[0007] Preferably, the stringer thickness is 1 to 10 mm.

[0008] Preferably, the thickness of a single triangular reinforcing rib is 1 to 5 mm.

[0009] Preferably, several triangular reinforcing ribs on the inner side of the two external corners of the stringers are symmetrically distributed about the stringers, and the spacing between every two triangular reinforcing ribs is 10 to 50 mm.

[0010] The beneficial effects of this utility model are:

[0011] In this invention, symmetrical triangular reinforcing ribs are designed on the inner side of the external corner of the stringer, which can increase the bending stiffness of the fuselage panel in the width direction. This not only restricts the bending deformation of the composite material skin in the width direction during the curing process, but also improves the deformation resistance of the fuselage panel in the width direction during use. No triangular reinforcing ribs are designed on the internal corner of the stringer, which can ensure that the bottom surface of the stringer is completely in contact with the skin under pressure when the adhesive film is not cured. After the adhesive film between the stringer and the skin is cured, it forms an interlocking structure with the triangular reinforcing ribs on the inner side of the external corner of the stringer, which plays a role in restricting the curing deformation.

[0012] In this utility model, the angle of the inner corner of the long stringer is designed to exceed the standard angle when the bottom surface of the long stringer is fully attached to the fuselage panel. When the bottom surface of the long stringer is pressed and fully attached to the skin, a downward pressure prestress is applied to the skin, which can resist the upward bending deformation caused by the curing of the skin and can reduce the curing deformation. Attached Figure Description

[0013] The accompanying drawings, which are provided to further illustrate the present invention and constitute a part of the present invention, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention.

[0014] Figure 1 This is a schematic diagram of the long girder structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the triangular reinforcing rib structure set at the external corner of the stringer in this utility model;

[0016] Figure 3 This is a bottom view of the long girder in this utility model;

[0017] Figure 4 This is a physical schematic diagram of the stringer in this utility model.

[0018] Attached image captions:

[0019] 1-Stringer, 2-Stringer external corner, 3-Stringer internal corner, 4-Triangular reinforcing rib. Detailed Implementation

[0020] This section will describe in detail the specific embodiments of the present utility model. The preferred embodiments of the present utility model are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present utility model, but they should not be construed as limiting the scope of protection of the present utility model.

[0021] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0024] Reference Figures 1-4 This utility model provides a composite material stringer, wherein the stringer 1 is fixed to the fuselage panel. The stringer 1 is made of carbon fiber reinforced epoxy resin composite material. The cross-section of the stringer 1 is a hat-shaped structure, and the hat-shaped cross-section of the stringer 1 has four corners, including two lower stringer internal corners 3 and two upper stringer external corners 2. The inner sides of the two stringer external corners 2 are provided with a number of triangular reinforcing ribs 4 at intervals (preferably, the total number of triangular reinforcing ribs 4 is selected according to the length of the stringer 1). The number of triangular reinforcing ribs 4 on the inner sides of the two stringer external corners 2 are symmetrically distributed about the stringer 1, and the spacing between every two triangular reinforcing ribs 4 is 10-50mm. A pre-deformation area is formed between the stringer internal corner and the fuselage panel. When the bottom surface of the stringer is pressed and fully adheres to the skin, a downward pressure prestress is applied to the skin, which can resist the upward bending deformation caused by the curing of the skin.

[0025] Preferably, the thickness of the stringer 1 is 1 to 10 mm.

[0026] Preferably, the thickness of a single triangular reinforcing rib 4 is 1 to 5 mm.

[0027] Specifically, the inner side of the long stringer corner 2 is designed with symmetrical triangular reinforcing ribs 4, which can increase the bending stiffness of the fuselage panel in the width direction. This not only restricts the bending deformation of the composite material skin in the width direction during the curing process, but also improves the deformation resistance of the fuselage panel in the width direction during use.

[0028] Furthermore, after the adhesive film between the stringer 1 and the skin is cured, it forms an interlocking structure with the triangular reinforcing rib 4 on the inner side of the stringer's external corner 2, which plays a role in restricting the curing deformation.

[0029] In this embodiment, there are no triangular reinforcing ribs 4 on the inner side of the two stringer corners 3, which can ensure that the bottom surface of the stringer 1 is fully pressed and adhered to the skin when the adhesive film is not cured; the design angle of the stringer corner 3 exceeds the standard angle when the bottom surface of the stringer 1 is fully adhered to the fuselage panel, and the design angle of the stringer corner 3 exceeds the standard angle by 1 to 20°.

[0030] Specifically, when the bottom surface of the stringer 1 is under pressure and fully adheres to the skin, applying downward prestress to the skin can resist the upward bending deformation caused by the skin curing, thus reducing curing deformation.

[0031] Example 1

[0032] A composite material stringer has a hat-shaped cross-section with four corners, including two lower concave corners 3 and two upper convex corners 2. Several triangular reinforcing ribs 4 are provided on the inner side of the two convex corners 2. The triangular reinforcing ribs 4 are symmetrically distributed about the stringer 1. The thickness of a single triangular reinforcing rib 4 is 3mm. The spacing between every two triangular reinforcing ribs 4 is 30mm. The design angle of the concave corner 3 exceeds the standard angle by 3°.

[0033] Without causing conflict, those skilled in the art can freely combine and use the above-mentioned additional technical features.

[0034] The above description is only a preferred embodiment of the present utility model. Any technical solution that achieves the purpose of the present utility model by essentially the same means shall fall within the protection scope of the present utility model.

Claims

1. A composite material stringer, characterized in that: The stringer is fixed to the fuselage panel. The stringer is made of carbon fiber reinforced epoxy resin composite material. The stringer has a hat-shaped cross-section with four corners. The four corners include two lower internal corners and two upper external corners. Several triangular reinforcing ribs are provided at intervals on the inner side of the two external corners. There are no triangular reinforcing ribs on the inner side of the two internal corners. A pre-deformation area is formed between the internal corners of the stringer and the fuselage panel.

2. The composite material stringer according to claim 1, characterized in that: The design angle of the inner corner of the stringer exceeds the standard angle when the bottom surface of the stringer is fully in contact with the fuselage panel, and the design angle of the inner corner of the stringer exceeds the standard angle by 1 to 10 degrees.

3. A composite material stringer according to claim 1, characterized in that: The thickness of the stringer is 1 to 10 mm.

4. A composite material stringer according to claim 1, characterized in that: The thickness of a single triangular reinforcing rib is 1–5 mm.

5. A composite material stringer according to claim 1, characterized in that: Several triangular reinforcing ribs are symmetrically distributed about the left and right sides of the two external corners of the stringers, and the spacing between every two triangular reinforcing ribs is 10-50mm.

Images