A crash-resistant fuselage lower energy-absorbing structure

Abstract

The present application belongs to the technical field of anti-impact design of aviation structures, and particularly relates to an anti-crash fuselage lower energy absorption structure. The structure comprises: the cross section of the fuselage frame is arc-shaped; the two ends of the cabin floor beam are connected to the fuselage frame; the lower fuselage beam is arranged in parallel below the cabin floor beam, the two ends of the lower fuselage beam are connected to the fuselage frame, and a storage space is formed between the lower fuselage beam and the cabin floor beam; two lower fuselage diagonal braces are symmetrically arranged, and the lower fuselage diagonal braces include a first diagonal brace section and a second diagonal brace section, the end of the first diagonal brace section is connected to the fuselage frame, and the end of the second diagonal brace section is connected to the lower fuselage beam, wherein the first diagonal brace section, the second diagonal brace section, the lower fuselage beam and the fuselage frame together form a parallelogram-like structure; two lower fuselage columns are symmetrically arranged, the upper end of the lower fuselage column is connected to the cabin floor beam, and the lower end is connected to the lower fuselage diagonal brace. The present application can reduce the peak value of the crash load.

Description

Technical Field

[0001] The present application belongs to the technical field of impact-resistant design of aviation structures, and in particular relates to an energy-absorbing structure for the lower part of a crash-resistant fuselage. Background Art

[0002] Crashworthiness is an important part of the safety assessment of civil aircraft. In an emergency crash environment, the aircraft mainly relies on the deformation and local damage of the cabin floor substructure to absorb the impact energy, reduce the aircraft crash overload, and protect the safety of the passengers.

[0003] Generally speaking, for wide-body aircraft or single-aisle large aircraft with more than 100 passenger seats, the part below the cabin floor is the cargo hold area, which has less designability. For small aircraft with 40 to 100 passenger seats, the space below the cabin is usually smaller and is not used as a cargo hold area for loading luggage. Therefore, the lower structure layout can be redesigned to improve the aircraft's crash resistance.

[0004] The impact load response of an aircraft after a crash is mainly affected by the fuselage structure. For small passenger aircraft, the space below the cabin is small, and the lower part of the cabin floor is generally supported by two columns. In this layout, due to the high initial contact stiffness, after the belly of the fuselage hits the ground, the columns are bent and broken in the area near the connection, while other areas of the columns hardly participate in plastic deformation. The overall energy absorption of the columns is limited, and a large load peak will be generated after the columns touch the ground. Secondly, due to the limited energy absorption space, the overall energy absorption effect of the aircraft's lower structure is not as good as that of large passenger aircraft. Therefore, it is necessary to design the energy absorption layout of the cabin lower structure of such small aircraft.

[0005] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0006] The purpose of the present application is to provide a crash-resistant lower fuselage energy-absorbing structure to solve at least one problem existing in the prior art.

[0007] The technical solution of this application is:

[0008] A crash-resistant fuselage lower energy absorption structure, comprising:

[0009] A fuselage frame, wherein the cross section of the fuselage frame is arc-shaped;

[0010] A cabin floor crossbeam, both ends of which are connected to the fuselage frame;

[0011] A fuselage lower cross beam, wherein the fuselage lower cross beam is arranged in parallel below the cabin floor cross beam, both ends of the fuselage lower cross beam are connected to the fuselage frame, and a receiving space is formed between the fuselage lower cross beam and the cabin floor cross beam;

[0012] The lower fuselage diagonal braces are symmetrically arranged in two pieces, the lower fuselage diagonal braces include a first diagonal brace section and a second diagonal brace section, the end of the first diagonal brace section is connected to the fuselage frame, and the end of the second diagonal brace section is connected to the lower fuselage cross beam, wherein the first diagonal brace section, the second diagonal brace section, the lower fuselage cross beam and the fuselage frame together form a parallelogram-like structure;

[0013] Two lower fuselage columns are symmetrically arranged, the upper ends of the lower fuselage columns are connected to the cabin floor crossbeams, and the lower ends are connected to the lower fuselage diagonal braces.

[0014] In at least one embodiment of the present application, the cabin floor cross beam and the fuselage lower cross beam are both arranged along the span direction of the aircraft.

[0015] In at least one embodiment of the present application, the lower fuselage cross beam and the lower fuselage diagonal brace are made of aluminum alloy material.

[0016] In at least one embodiment of the present application, the position where the lower fuselage column is connected to the lower fuselage diagonal brace is located at the connection between the first diagonal brace section and the second diagonal brace section.

[0017] In at least one embodiment of the present application, the lower fuselage pillar is C-shaped and is made of a laminated structure of composite materials containing lost layers.

[0018] In at least one embodiment of the present application, the lower fuselage column is provided with a plurality of regions from the upper end to the lower end, and the plies of each region decrease successively from the upper end to the lower end.

[0019] The invention has at least the following beneficial technical effects:

[0020] The energy-absorbing structure of the lower part of the crash-resistant fuselage of the present application can reduce the peak value of the crash load, prolong the load action time, improve the crash suitability of the fuselage structure, and improve the crash safety of the occupants in an emergency crash environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the energy absorption structure of the lower part of the crash-resistant fuselage according to one embodiment of the present application;

[0022] Figure 2 It is a schematic diagram of the size layout of the energy absorption structure of the lower part of the crash-resistant fuselage according to one embodiment of the present application;

[0023] Figure 3It is a schematic diagram of the lower fuselage pillar of one embodiment of the present application.

[0024] in:

[0025] 1-fuselage frame; 2-cabin floor crossbeam; 3-fuselage lower crossbeam; 4-fuselage lower diagonal brace; 5-fuselage lower column. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0027] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0028] The following is combined with Figures 1 to 3 This application is described in further detail.

[0029] The present application provides a crash-resistant lower fuselage energy absorption structure, comprising: a fuselage frame 1, a cabin floor crossbeam 2, a lower fuselage crossbeam 3, a lower fuselage diagonal brace 4 and a lower fuselage column 5.

[0030] like Figure 1As shown, the cross section of the fuselage frame 1 is arc-shaped. Both ends of the cabin floor cross beam 2 are connected to the fuselage frame 1, and the lower fuselage cross beam 3 is arranged parallel to the lower part of the cabin floor cross beam 2. Similarly, both ends of the lower fuselage cross beam 3 are connected to the fuselage frame 1, and a receiving space is formed between the lower fuselage cross beam 3 and the cabin floor cross beam 2, and the lower fuselage diagonal brace 4 and the lower fuselage column 5 are installed in the receiving space. Among them, two lower fuselage diagonal braces 4 are symmetrically arranged, and the lower fuselage diagonal braces 4 include a first diagonal brace section and a second diagonal brace section that are connected. There is an angle between the first diagonal brace section and the second diagonal brace section, and the angle is an obtuse angle. The end of the first diagonal brace section away from the second diagonal brace section is connected to the fuselage frame 1, and the end of the second diagonal brace section away from the first diagonal brace section is connected to the lower fuselage cross beam 3, wherein the first diagonal brace section, the second diagonal brace section, the lower fuselage cross beam 3 and the fuselage frame 1 together form a parallelogram-like structure; two lower fuselage columns 5 are symmetrically arranged, the upper ends of the lower fuselage columns 5 are connected to the cabin floor cross beam 2, and the lower ends are connected to the lower fuselage diagonal braces 4.

[0031] In the preferred embodiment of the present application, the cabin floor beam 2 and the fuselage lower beam 3 are arranged along the aircraft span. The position where the fuselage lower column 5 is connected to the fuselage lower diagonal brace 4 is located at the connection between the first diagonal brace section and the second diagonal brace section.

[0032] The anti-crash fuselage lower energy absorption structure of the present application is as follows: Figure 2 As shown, the vertical distance h from the lowest part of the fuselage to the upper surface of the cabin floor beam 2 remains unchanged, and the size layout of each part meets the following requirements:

[0033] h=h1+h2+l2sina

[0034] Wherein, h1 is the vertical distance from the lowest part of the fuselage to the upper surface of the lower fuselage beam 3, h2 is the vertical distance from the upper surface of the first diagonal bracing section to the upper surface of the cabin floor beam 2, l2 is the length of the second diagonal bracing section, and a is the angle between the second diagonal bracing section and the horizontal plane;

[0035] Because the fuselage frame diameter of the cabin lower structure remains unchanged, l2 can be determined after h1, h2 and l1 are determined. l1 is the distance from the center of the lower fuselage cross beam 3 to the connection between the second diagonal bracing section and the lower fuselage cross beam 3.

[0036] In addition to the structural layout design, the crash-resistant fuselage lower energy absorption structure of the present application also makes full use of the excellent energy absorption characteristics of metal materials and the advantages of composite materials, which are light and highly designable. In the preferred embodiment of the present application, the fuselage lower cross beam 3 and the fuselage lower diagonal brace 4 are made of aluminum alloy materials with good ductility, which fully absorb the crash energy through plastic deformation during the crash. In the preferred embodiment of the present application, Figure 3As shown, the lower fuselage column 5 is C-shaped and is made of a composite material laminate structure containing lost layers. The composite material laminate structure containing lost layers refers to dividing the lower fuselage column 5 from the upper end to the lower end into multiple areas, and the plies in each area are interconnected, wherein some plies in certain areas can be discarded when they pass to other areas due to the need for ply optimization. In this embodiment, the lower fuselage column 5 can be designed to have a reduced number of plies in each area from the upper end to the lower end. During a crash, when the crash load is transmitted to the lower fuselage column 5, a step-by-step failure from bottom to top can be achieved, and the lower fuselage column 5 can be gradually crushed and damaged to improve the energy absorption efficiency.

[0037] The anti-crash fuselage lower energy absorption structure of the present application is arranged in multiple pieces along the axial direction of the aircraft, which does not affect the installation of necessary equipment such as aircraft fuel pipelines, cables, and control mechanisms. The deformation and energy absorption during the crash can be divided into three levels. The first-level energy absorption area is composed of the area surrounded by the lower fuselage cross beam 3 and the fuselage frame 1 below the lower fuselage cross beam 3. After the crash load is transmitted to this area, energy is mainly absorbed through the bending plastic deformation of the fuselage frame 1 and the lower fuselage cross beam 3. The second-level energy absorption area is composed of the area surrounded by the lower fuselage cross beam 3, the lower fuselage diagonal brace 4 and the fuselage frame 1. The approximate parallelogram formed by this area is conducive to the coordinated deformation of the structure. This area absorbs energy through the bending plastic deformation of the lower fuselage cross beam 3, the lower fuselage diagonal brace 4 and the fuselage frame 1. The third-level energy absorption area is composed of the area surrounded by the first diagonal brace section of the lower fuselage diagonal brace 4, the lower fuselage column 5 and the cabin floor crossbeam 2. This area mainly absorbs energy through the progressive crushing of the lower fuselage column 5 made of composite material.

[0038] The crash-resistant lower fuselage energy absorption structure of the present application maintains the connection relationship between the fuselage frame 1, the cabin floor crossbeam 2, the lower fuselage crossbeam 3, the lower fuselage diagonal brace 4 and the lower fuselage column 5 unchanged, and a series of layout schemes can be generated by changing the positions of the connection points of these components. By optimizing the layout parameters, the optimal energy absorption layout can be obtained to achieve orderly destruction during the crash and control of the crash load waveform. The configuration of the lower fuselage column 5 is not limited to the C-type structure, and the ply and layer loss number of the composite material lower fuselage column 5 can also be further optimized.

[0039] The crash-resistant lower fuselage energy absorption structure of this application is designed based on the hierarchical and controllable design principle of the lower fuselage structure, combined with the layout characteristics of the lower cabin of small aircraft. First, the lower fuselage structure layout is designed to establish a hierarchical energy absorption mechanism to allow more structures to participate in plastic deformation to absorb crash energy; secondly, advanced composite energy absorption elements are introduced to further improve the energy absorption efficiency. This application also has the advantages of light weight and small space occupation. The structure is highly designable, modular processing and flexible installation can be achieved, and it has a wide range of application scenarios.

[0040] The anti-crash fuselage lower energy-absorbing structure of the present application can reduce the peak crash load, prolong the load action time, improve the crash suitability of the fuselage structure, and improve the crash safety of passengers in an emergency crash environment without reducing the cabin floor support strength and support stiffness and ensuring sufficient installation space for necessary equipment. It meets the anti-crash design requirements of various types of aircraft fuselage structures and has broad application prospects.

[0041] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A crash-resistant fuselage lower energy absorption structure, characterized in that: include: A fuselage frame (1), wherein the cross section of the fuselage frame (1) is arc-shaped; A cabin floor crossbeam (2), wherein both ends of the cabin floor crossbeam (2) are connected to the fuselage frame (1); A fuselage lower cross beam (3), the fuselage lower cross beam (3) being arranged in parallel below the cabin floor cross beam (2), the two ends of the fuselage lower cross beam (3) being connected to the fuselage frame (1), and a receiving space being formed between the fuselage lower cross beam (3) and the cabin floor cross beam (2); Two lower fuselage diagonal braces (4) are symmetrically arranged, the lower fuselage diagonal braces (4) comprising a first diagonal brace section and a second diagonal brace section, the end of the first diagonal brace section being connected to the fuselage frame (1), and the end of the second diagonal brace section being connected to the lower fuselage cross beam (3), wherein the first diagonal brace section, the second diagonal brace section, the lower fuselage cross beam (3) and the fuselage frame (1) together form a parallelogram-like structure; Two lower fuselage columns (5) are symmetrically arranged, the upper ends of the lower fuselage columns (5) are connected to the cabin floor crossbeam (2), and the lower ends are connected to the lower fuselage diagonal braces (4).

2. The crash-resistant fuselage lower energy-absorbing structure according to claim 1, characterized in that: The cabin floor cross beam (2) and the fuselage lower cross beam (3) are both arranged along the aircraft span direction.

3. The crash-resistant fuselage lower energy-absorbing structure according to claim 1, characterized in that: The lower fuselage cross beam (3) and the lower fuselage diagonal brace (4) are made of aluminum alloy material.

4. The crash-resistant fuselage lower energy-absorbing structure according to claim 1, characterized in that: The position where the lower fuselage column (5) is connected to the lower fuselage diagonal brace (4) is located at the connection between the first diagonal brace section and the second diagonal brace section.

5. The crash-resistant fuselage lower energy-absorbing structure according to claim 1, characterized in that: The lower fuselage column (5) is C-shaped and is made of a laminated structure containing a lost layer of composite material.

6. The crash-resistant fuselage lower energy-absorbing structure according to claim 5, characterized in that: The lower fuselage column (5) is provided with a plurality of regions from the upper end to the lower end, and the ply of each region decreases successively from the upper end to the lower end.

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