RU2655585C2 - Node of the fuselage compartment with mesh and traditional constructive-power circuits - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to the field of aviation structures with various structural-power circuits (SPC), in particular, to the grid power structure of the fuselage compartment of a civil aircraft. Joint unit of the fuselage compartments with a mesh and traditional SPC contains spiral ribs and an end ring rib of the mesh compartment. Moreover, the spiral ribs are released beyond the edge annular rib for a distance of at least 10 mm in such a way that the intersecting ribs form an arc of a circle with a radius of at least 10 mm. Metal frame with grooves is placed close to the end ring rib, into which are placed spiral ribs outside the end rib, covered with a lid, which is tightened to the metal frame by bolts. Sheathing and stringers of the compartment with traditional SPC are connected to the metal frame through fittings by means of a bolted connection. Sheathing of adjacent compartments is attached with an overlap to the metal frame by means of a bolted connection. Moreover, the width of the end annular rib is not less than the width of the spiral ribs.

EFFECT: necessary strength of the connection of the mesh compartment with the compartments of the traditional SPC fuselage is being achieved.

1 cl, 3 dwg

Description

The invention relates to the field of development of power composite and metal composite aircraft structures with various structural power schemes (KSS), in particular to a mesh power structure of the fuselage compartment of a civil aircraft, and can be used to develop aviation technology.

Known junction of the compartments of the fuselage of the aircraft, containing the skin of the mating sealed and non-sealed compartments, reinforced by stringers, and a pressure gauge located at the junction of the sealed and non-sealed compartments (RF Patent No. 2472671, IPC ВСС 1/10, Sukhoi Civil Aircraft CJSC, 01.09. 2011).

The disadvantage of this design, in relation to the connection of the mesh composite compartment of the fuselage and the compartment of the fuselage with the traditional KSS (based on skins reinforced by stringers and frames), is the low strength characteristics of the structure in the area of the connection of the mesh composite frame with fittings. This design uses a bolted connection of mesh ribs and fittings, for which holes are drilled in unidirectional composite ribs. Obviously, any hole in a unidirectional composite structure leads to a significant decrease in the strength characteristics of the composite element. In addition, the strength characteristics of a unidirectional composite structure under the shear force of the bolt are an order of magnitude lower than the tensile / compression strength characteristics of the rib, which does not allow the necessary strength of this type of joints to be provided for mesh composite structures.

Known butt plate for connecting the fuselage compartments containing a strip designed to create a jumper between the fuselage compartments, a shear element superimposed on the strip, and a connecting element between the strip and shear element, as well as a method for connecting the fuselage compartments connected thereto (RF Patent No. 2564561, IPC B64C 1/12, Dze Boeing Company (USA), 04/04/2011).

The disadvantage of this design is the low strength characteristics of the structure in the zone of connection of the outer skin of the mesh compartment with the butt plate. The main power element of the mesh compartment is a composite mesh frame that accepts all types of mechanical loads (tension, compression, bending, torsion), and the skin is a non-force element, the main function of which is to create a smooth aerodynamic surface of the fuselage compartment. The use of a butt plate with such a sheathing to connect the mesh compartment with the compartments of traditional KSS will not allow to provide the necessary strength of the connection.

Known flange connection of the mesh compartments with adjacent compartments of the fuselage, the closest in design features to the present invention and taken as a prototype. This solution is known and is used in serial mesh designs manufactured at the Central Scientific Research Institute of Mechanical Engineering (see articles: A.F. Razin, Yu.O. Bakhvalov, S. A. Petrokovsky, V. P. Polinovsky, A. G. Bakhtin “Design Features composite mesh compartments associated with the conditions of their loading "// Designs from composite materials. - No. 4. - 2009. - P. 34-43 and VV Vasiliev, AF Razin" Anisogrid composite lattice structures for spacecraft and aircraft applications)) // Composite Structures. - 2006. - Vol. 76.- S. 182-189).

The disadvantage of this design is also the low strength characteristics of the structure in the joint zone, since longitudinal holes in the end annular ribs are provided for its implementation. The connection is carried out by means of studs and two nuts, tightening the joined structures. When tensile loads are applied to the flange docking unit, significant stress concentrations arise in the end annular rib. This leads to the fact that the destruction of the structure occurs in the end ribs at a loading level of longitudinal and spiral force ribs, which is only ~ 50% of their level of bearing capacity. This circumstance does not allow the use of this type of joint for the construction of the fuselage compartments of civil aircraft.

The technical result is to provide the necessary strength of the junction of the mesh compartment with the compartments of the traditional KSS fuselage of a civilian aircraft.

The technical result is achieved by the fact that at the junction of the fuselage compartments with the mesh and traditional KSS, containing spiral ribs and an end annular rib of the mesh compartment, the spiral ribs are released beyond the end of the annular rib to a distance of at least 10 mm so that the intersecting ribs form an arc of a circle with a radius of at least 10 mm, close to the end annular rib there is a metal frame with grooves in which spiral ribs are placed outside the end rib, covered with a lid tightened to m the metallic frames by bolts, plating and stringers compartment with conventional CMP are connected to a metal frame attachment through the fittings by bolting plating adjacent compartments are attached to the metal frames overlap by bolting, the width of the end annular edge of at least the width of the spiral ribs.

The figure 1 shows a diagram of the junction of the mesh compartment of the fuselage with the compartment with the traditional KSS on the inside of the fuselage.

The figure 2 shows a diagram of the junction node of the mesh compartment of the fuselage with a compartment with a traditional KSS on the outside of the fuselage without skin.

The figure 3 shows a cross section of the junction of the mesh compartment of the fuselage with the compartment with the traditional KSS in a plane parallel to the axis of the fuselage.

The junction of the fuselage compartments with the mesh and traditional KSS includes the following main elements:

- spiral ribs 1, released beyond the end of the annular rib 2 to a distance of at least 10 mm so that the intersecting ribs form an arc of a circle with a radius of at least 10 mm;

- a metal frame with grooves 3 located close to the end annular rib 2, in which the spiral ribs 1 are placed outside the end rib 2,

- a cover 4, covering the spiral ribs 1, placed in the grooves of the metal frame 3, and pulled to the metal frame 3 by bolts 5;

- fittings 6 used to connect the casing 7 and stringers 8 of the compartment with a traditional KSS with a metal frame 3 by means of a bolted connection.

In the proposed joint, the flow of forces in the docking zone is transmitted through a metal frame 3, in the grooves of which are placed spiral ribs 1. Streams of tensile forces are transmitted from the spiral ribs 1 of the mesh compartment to the metal frame 3 and then through the fittings 6 to the stringers 8 and the lining 7 of the compartment with traditional css. Streams of compressive forces are transmitted from the end annular rib 2 of the mesh compartment, as well as from the spiral ribs 1 to the metal frame 3 and then through the fittings 6 to the stringers 8 and the lining of the compartment 7 with the traditional KSS. When this ribs 1 are loaded in the longitudinal direction, which ensures reliability and high strength of the connection. This junction allows you to maximize the strength characteristics of the spiral ribs 1 of the mesh compartment, reduce stress concentrators in the docking zone and thereby provide the necessary strength of the connection of the fuselage compartments of a civilian aircraft.

The main advantages of the proposed node junction of the fuselage compartments with mesh and traditional KSS in comparison with analogues are:

1) reducing the level of stress concentration in the docking zone, which allows to provide the necessary strength of the connection of the fuselage compartments of a civilian aircraft;

2) the maximum implementation of the strength characteristics of the spiral ribs of the mesh compartment;

3) the possibility of manufacturing a metal frame integrated with the end ring edge of the mesh compartment, which will ensure reliable connection of the compartments without gaps and backlashes.

Claims (1)

The junction of the fuselage compartments with the mesh and traditional structural-power schemes, containing spiral ribs and an end annular rib of the mesh compartment, characterized in that the spiral ribs are released beyond the end of the annular rib by a distance of at least 10 mm so that the intersecting ribs form an arc of a circle with a radius of at least 10 mm, close to the end annular rib there is a metal frame with grooves in which spiral ribs are placed outside the end rib, covered with a lid, is tightened to the metal frame with bolts, the sheathing and stringers of the compartment with the traditional KSS are connected to the metal frame through fittings by means of a bolt, the sheathing of the adjacent compartments is overlapped to the metal frame by means of a bolt, and the width of the end ring rib is not less than the width of the spiral ribs.

Images