Floor beam structure

Abstract

A floor crossbeam structure is positioned at a connection of a pressure floor and a pressure end frame of an aircraft, the floor crossbeam structure comprising a first profile member and a second profile member, which are configured in a structure that abuts a stringer of the pressure floor and a post of the pressure end frame, a connecting angle member having an inner side and an outer side, the outer side fixedly engaging the first profile member and the second profile member, and a plurality of corner boxes fixedly mounted in the inner side of the connecting angle member.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the field of fuselage structures of aircraft structures, and in particular to a floor beam structure with corner boxes at the connection between the airtight floor and the end frame of a civil aircraft. BACKGROUND

[0002] In civil aircraft, the fuselage structure generally comprises a frame and a floor structure, which are important components of the fuselage structure and provide airtightness and shape for the passenger cabin of the aircraft. Generally, the airtight plate of the floor structure is not directly installed to the end frame, because fatigue problems and airtightness problems will be caused. Therefore, the floor structure generally further comprises a beam and a stringer. The beam is generally fixed to the frame of the fuselage at both ends, the stringer is lapped on the beam, and the airtight plate is installed on the support structure composed of the stringer and the beam. In addition, the aircraft also comprises a column, which provides support for the end frame structure in the vertical direction.

[0003] Currently, at the rear of the main cabin of the aircraft, the connection corner between the horizontal airtight floor and the vertical airtight end frame will cause fatigue problems under the action of airtight load due to the coordinated deformation. Therefore, in the actual design, a floor beam structure is arranged at the connection between the airtight floor and the end frame to bear the airtight load transmitted by the airtight floor and the airtight end frame and to provide a sealing effect. The cross-sectional shape of the conventional beam includes C-shaped, I-shaped, etc. These types of cross sections ensure that the floor beam can bear the airtight load between the airtight floor and the airtight end frame and other loads.

[0004] Due to the mismatch of the stiffness of the floor beam and the adjacent structure (i.e. the floor stringer and the end frame column), the stress at the triangular area (also known as the R area in the field of structural design) of the L or T type part of the floor beam is very high under the forced displacement caused by the deformation of the adjacent structure, even if a material with better fatigue performance is replaced, the fatigue problem at this place cannot be solved.

[0005] Currently, some models solve this problem by increasing weight and cost, reducing processability and maintainability, and adopt the form of overall machining of the floor stringer and the end frame column. However, this way still inevitably has a high machining cost and is not convenient for maintenance.

[0006] Therefore, it is currently desirable to have a beam structure that can conveniently improve the local stiffness of the floor beam at a lower machining cost. SUMMARY

[0007] In order to solve the fatigue problem of the floor beam structure at the connection part of the airtight floor and the airtight end frame and the inconvenience of maintenance, the floor beam structure is designed by combining profile members and sheet bending parts. The machined corner box structure is installed at the corner of the column and the floor beam, the local stiffness of the floor beam is improved, and the stress in the R area of the floor beam is reduced. In addition, the processing cost of the beam structure is low, the assembly process is good, and the maintenance performance is good.

[0008] Specifically, the floor beam structure is positioned at the connection part of the airtight floor and the airtight end frame of the aircraft, and comprises: a first profile member and a second profile member, which are respectively configured to abut the longitudinal beam of the airtight floor and the column of the airtight end frame; a connecting angle member having an inner side and an outer side, the outer side fixedly engaging the first profile member and the second profile member; and a plurality of corner boxes fixedly installed in the inner side of the connecting angle member.

[0009] Preferably, the first profile member and / or the second profile member has a flange to bear the airtight load transmitted by the airtight floor and the airtight end frame.

[0010] Preferably, the first profile member and the second profile member have the same structure.

[0011] In the embodiment of the present application, the connecting angle member is an L-shaped connecting angle.

[0012] Further, the connecting angle member seals between the airtight floor and the airtight end frame.

[0013] Preferably, the number of corner boxes matches the number of longitudinal beams of the airtight floor to provide local support at each section where the floor beam structure and the longitudinal beam abut, improving the local stiffness.

[0014] In the embodiment of the present application, the corner boxes are fixed relative to the connecting angle member by screwing.

[0015] Preferably, the connecting angle member is made of titanium alloy material.

[0016] The present application also provides a method for installing the above-mentioned floor beam structure at the connection part of the airtight floor and the airtight end frame, comprising the following steps: connecting the airtight end frame with the airtight end frame column to form an integral assembly structure; positioning the airtight floor, the airtight end frame and the floor longitudinal beam, then positioning the first profile member and the connecting angle member, and temporarily connecting the first profile member and the connecting angle member; adjusting the position of the second profile member according to the assembly of the first profile member and the connecting angle member and tightening; leaving the rivet at the position where the corner box is to be connected; and fixing the corner box relative to the first profile member, the second profile member and the connecting angle member.

[0017] Additional features and advantages of the described floor beam structure will be set forth in the detailed description which follows, and will be readily apparent to those skilled in the art from that description, including the detailed description which follows, and the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] With reference to the above objects, the technical features of the present application are clearly described in the following claims, and the advantages thereof will be apparent from the following detailed description with reference to the attached drawings, which show by way of example the preferred embodiments of the present application, without limiting the scope of the inventive concept.

[0019] Figure 1 An isometric view of a perimeter connection of a floor beam structure according to an embodiment of the present application is shown;

[0020] Figure 2 A front view of a perimeter connection of a floor beam structure according to an embodiment of the present application is shown;

[0021] Figure 3 A partial view of a perimeter connection of a floor beam structure according to an embodiment of the present application is shown;

[0022] Figure 4 An isometric view of a portion of a floor beam structure according to an embodiment of the present application is shown;

[0023] Figure 5 An exploded view of a portion of a floor beam structure according to an embodiment of the present application is shown; and

[0024] Figure 6 A side view of a portion of a floor beam structure according to an embodiment of the present application is shown.

[0025] REFERENCE NUMERALS

[0026] 1 floor beam structure

[0027] 2 air-tight floor

[0028] 3 air-tight end frame

[0029] 4 upright post

[0030] 5 floor beam

[0031] 11 first profile member

[0032] 12 second profile member

[0033] 13 connecting angle member

[0034] 14 corner box

[0035] 111, 121 flange

[0036] 141 stringers DETAILED DESCRIPTION

[0037] The present application will be further described with reference to the drawings and embodiments, but should not be construed as being limited to any of the embodiments.

[0038] The orientation terms "horizontal", "vertical", and the like, are described with reference to the position of the components or elements when viewed in a front view of the aircraft.

[0039] The term "outer" is used herein to refer to the protruding side of an object, and "inner" refers to the recessed side.

[0040] It should be understood that "first" and "second" herein can be interchanged without affecting the description of the embodiments.

[0041] Figures 1-3 The general position of a floor beam structure 1 for a civil aircraft according to an embodiment of the present application is shown, Figures 4-6 The specific configuration of the floor beam structure 1 of this embodiment is shown (only a portion of the floor beam structure 1 is shown for simplicity). The floor beam structure 1 is installed at the connection portion of the airtight floor 2 and the airtight end frame 3, abutting the upright 4 of the airtight end frame 3 and the floor longitudinal beam 5, the airtight end frame 3 being integrally formed with the upright 4. The floor beam structure in this embodiment, except for the reinforcing corner box 14 (to be described below), is made of a combination of profiled members and bent sheet members, has a small overall weight, a small raw material size, a low processing cost, and good assembly workability, i.e., it is easy to adjust the installation position during assembly. The floor beam structure 1 is composed of a first profiled member 11, a second profiled member 12, a connecting angle member 13, and a plurality of corner boxes 14. These members will be described in detail below.

[0042] As shown, the first profiled member 11 and the second profiled member 12 are positioned perpendicular to each other to abut the upright 4 of the airtight end frame 3 and the floor longitudinal beam 5, respectively. Specifically, the first profiled member 11 and the second profiled member 12 are angle members having an L-shaped cross section, respectively, with flanges 111 and 121, respectively, the L-shaped cross section allowing the first profiled member 11 and the second profiled member 12 to have improved ability to withstand the airtight load transmitted by the airtight floor 2 and the airtight end frame 3. It should be understood that other shapes of cross sections of other shapes capable of withstanding the airtight load transmitted by the airtight floor 2 and the airtight end frame 3 are also possible. It should also be understood that in this embodiment, the first profiled member 11 and the second profiled member 12 preferably have the same structure, but in other embodiments, the first profiled member 11 and the second profiled member 12 can have different structures according to actual needs.

[0043] As shown in the figure, the floor beam structure 1 comprises a connecting angle member 13 formed of titanium alloy material with better fatigue performance, which has an inner side and an outer side, and the outer side of the connecting angle member 13 fixedly engages the first profile member 11 and the second profile member 12 to transmit the load between the first profile member 11 and the second profile member 12. Further, the connecting angle member 13 plays a sealing role with respect to the gap between the air-tight floor 2 and the air-tight end frame 3, thereby improving the coordinated deformation capability. In the present application, the connecting angle member 13 is an L-shaped sealing connecting angle, which Figure 6 As can be seen, the two "sides" of the L-shaped sealing connecting angle respectively fixedly engage the first profile member 11 and the second profile member 12.

[0044] As shown in the figure, the floor beam structure 1 further comprises corner boxes 14, which are triangular rigid members with vertical ribs 141, and the corner boxes 14 are fixedly installed in the inner side of the connecting angle member 13 to improve the local rigidity of the floor beam structure 1, and also reduce the forced displacement, thereby reducing the high stress of the connecting angle member 13 at the R area caused by the coordinated deformation of the air-tight floor 2 and the air-tight end frame 3, and improving the fatigue quality of the floor beam structure 1 itself.

[0045] The corner box 14 is formed by machining, so that it can better fit with the adjacent sheet metal structure to achieve better assembly process. The corner box 14 can be reshaped according to the actual shape of the sheet metal part after forming. Since the floor longitudinal beam 5 and the air-tight end frame column 4 have large rigidity, and the rigidity of the connecting angle member 13 is usually small, without the reinforced corner box 14, the deformation amount on both sides of the connecting angle member 13 is completely equal to the connected floor longitudinal beam and air-tight end frame column, and the stress at the R area of the thickened L-shaped connecting angle is even larger. After replacing a plurality of materials for calculation, it is found that the stress at the R area is proportional to the elastic modulus E. Similarly, when designing the corner box 14, it is found that the body rigidity of the corner box 14 cannot be too large, otherwise the stress at the R area of the vertical rib 141 and the bottom edge of the reinforced corner box 14 may be too large, which may cause new fatigue problems. Therefore, the corner box 14 of the present application adopts a vertical rib structure with a flange, which reduces the forced displacement to a certain extent, ensures that the stress at the fatigue sensitive part of the reinforced corner box is reasonable, and meets the fatigue life requirement.

[0046] Preferably, the number of corner boxes 4 matches the number of longitudinal beams 5 to provide local reinforcement at each section where the floor beam structure 1 and the longitudinal beam 5 abut. This reinforced corner box 14 adopts an independent positioning and installation mode. For the in-service aircraft without the corner box 14, if a crack occurs at the R area of the connecting angle member 13 (for example, the L-shaped sealing connecting angle in the present embodiment), the reinforced corner box 14 can be directly installed at the crack area by using fasteners to repair the structure without changing other structures after removing the crack, which can greatly reduce the maintenance cost on the route.

[0047] The present application also provides a method for installing a floor beam structure with an angle box at the connecting part of a civil aircraft air-tight floor and an air-tight end frame, comprising the following steps:

[0048] In the assembly stage of the component, the air-tight end frame 3 is connected with the air-tight end frame column 4 to form an integral assembly structure; in the assembly stage of the section, the positioning of the air-tight floor 2, the air-tight end frame 3 and the floor longitudinal beam 5 is completed by using a tool, then the first profile member 11 and the connecting angle member 13 are positioned according to the tool, and the first profile member 11 and the connecting angle member 13 are connected by using temporary fasteners; according to the assembly condition of the first profile member 11 and the connecting angle member 13, the position of the second profile member 12 is adjusted and fastened by using relevant fasteners; the riveting is left at the position where the angle box 14 is to be connected; and the angle box 14 is riveted with the rest of the structure (including the first profile member 11, the second profile member 12 and the connecting angle member 13). It should be understood that the angle box 14 can also be fixed relative to the connecting angle member 13 in other ways.

[0049] The air-tight floor and end frame connecting part floor beam structure with an angle box of the civil aircraft of the present application has the advantages that a combined beam structure is adopted, the processing cost is low, the assembly process is good, and the maintenance performance is good; the angle box structure improves the local stiffness of the floor beam and improves the fatigue quality of the air-tight floor and air-tight end frame connecting part; and the in-service aircraft modification and repair can directly use the original fasteners, greatly reducing the maintenance cost.

[0050] Although the structure and installation method of the present application have been described above in combination with the preferred embodiments, it should be recognized by those skilled in the art that the above examples are only used for illustration and cannot be regarded as a limitation of the present application. Therefore, the present application can be modified and changed, and these modifications and changes will fall within the scope defined by the appended claims.

Claims

1. A floor beam structure, wherein the floor beam structure is positioned at the connection between the airtight floor and the airtight end frame of an aircraft, the floor beam structure comprising: The first profile component and the second profile component are respectively configured to abut against the longitudinal beam of the airtight floor and the column of the airtight end frame; A connecting angle member having an inner side and an outer side, the outer side being fixedly joined to the first profile member and the second profile member; as well as Multiple corner boxes are fixedly installed inside the connecting corner member.

2. The floor beam structure as described in claim 1, characterized in that, The first profile component and / or the second profile component have flanges.

3. The floor beam structure as described in claim 1, characterized in that... The first profile component and the second profile component have the same structure.

4. The floor beam structure as described in claim 1, characterized in that, The connecting angle member is an L-shaped connecting angle member.

5. The floor beam structure as described in claim 4, characterized in that, The connecting angle member seals between the airtight floor and the airtight end frame.

6. The floor beam structure as described in claim 1, characterized in that, The number of corner boxes matches the number of longitudinal beams in the airtight floor.

7. The floor beam structure as described in claim 1, characterized in that, The corner box is fixed relative to the connecting corner member by screwing.

8. The floor beam structure as described in claim 1, characterized in that, The connecting angle member is made of titanium alloy.

9. A method for installing a floor beam structure as described in any one of claims 1 to 8 at the connection between an airtight floor and an airtight end frame, comprising the following steps: Connect the airtight end frame to the airtight end frame column to form an integrated force transmission component structure; Position the airtight floor, the airtight end frame, and the floor longitudinal beams; then position the first profile component and the connecting corner component, and temporarily connect the first profile component and the connecting corner component. Based on the assembly status of the first profile component and the connecting angle component, the position of the second profile component is adjusted and tightened. Leave rivets at the locations where the corner boxes will be connected; as well as The corner box is fixed relative to the first profile member, the second profile member, and the connecting corner member.

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