RU2495786C1 - Butt joint panels from polymer composite - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to production of structures including butt joints of panels from polymer composites, particularly, to jointing of structural aircraft parts (torsion boxes, wing, stabilisers) from said polymer composites. Said butt joint comprises two connectable panels, each including lining and stiffness elements. Said panels are partially overlapped by composite butt strap, its one side being connected with first panel and another one with second panel. Said strap overlaps partially the ends of aforesaid stiffness elements. Said butt joint comprises extra three metal plates rigidly butted to comprises butt strap and two panels. Area of larger metal plate corresponds to that of composite butt strap to equal the sum of smaller metal plates. Metal needles are rigidly secured at one surface of said metal plates and inserted therein. Metal sleeves are fitted in the plates. Metal plate smooth surface are tightly pressed together, butted and bolted together, said bolts passing through bores made in panels and sleeves fitted plates.

EFFECT: efficient transfer of forces via mated elements, high bearing capacity, lower weight, simple fabrication and multiple assembly/disassembly.

6 cl, 5 dwg

Description

The invention relates to the field of manufacturing structures containing docking joints of panels made of polymer composite material (PCM), and can be used when docking overall aircraft parts from PCM (wing coffers, stabilizer).

A docking device is known between a front mount and two lateral caissons of a horizontal airplane stabilizer, consisting of a front mount, a front connecting plate, an upper connecting plate, a lower connecting plate and a “rib” connecting piece (US patent No. 2010/0127127 A1, class B64C 1 / 06, 2009).

The disadvantage of this invention is that due to the large number of fasteners in the design, there is a double coefficient of uneven distribution of efforts across the bolts. Poor PCM work on crushing leads to an increase in the thickness of the casing, compared with metal. A large number of used mechanical fasteners significantly affects the overall weight of the structure.

However, it is much more important that the reliability of such a joint to a very large extent depends on the concentration of stresses around the holes, which increases sharply in the presence of bumps, seizures and delaminations associated with the cutting of holes, which sharply reduces the work of the joint on crushing. It is difficult to avoid them due to the complexity of high-quality drilling of holes in the PCM. This is even more dangerous when their number is in the hundreds, and for the occurrence of a problem one poorly made hole is enough.

The closest adopted for the prototype is the connection of the reinforcing element with a part of the layered material of the aircraft (EP 1099537, CL B29C 70/24, 1999).

According to the patent, the connection of the reinforcing element with the upper or lower surface of the laminated plastic part (hereinafter referred to as the layered part) is carried out by means of fastening needle elements embedded inside them, which prevent the reinforcing element from separating from the layered part.

The laminate may be aircraft skin.

The fastening needle elements embedded inside the reinforcing element remain in the installed position.

Embedded fastening needle elements may extend through the reinforcing element.

Embedded inside the reinforcing element, the fixing needle elements can be made in the form of pins or piercing elements.

The pins or piercing elements can be embedded in the reinforcing element and in the layered part almost perpendicular to the plane of the layered part.

The pins or piercing elements can pass in the layered part only through those layers that experience a peeling load.

The reinforcing element can be installed on the layered part after the process of its laying out and molding.

The reinforcing element may be a structural element capable of absorbing a load, or a layered material in the form of a preform.

Between the reinforcing element and the laminated part along their edges or in the area between the edges can be used glue or a connecting layer.

Attached needle elements embedded inside the reinforcing member may extend into the adhesive or bonding layer.

The reinforcing element connected to the laminated part can be made in the form of a simple lining, composite lining or brand.

This connection can be used to install a reinforcing element on the layered parts of the aircraft, which can be made of reinforced layered material.

The use of this connection when docking overall parts from PCM (wing caissons, stabilizer) will have the following disadvantages:

- in the case of the introduction of fasteners into unformed PCM parts, complex, large-sized and energy-intensive heated equipment is required to ensure the required geometry and the final simultaneous molding of both PCM parts to be joined and the formation of a joint;

in the case of the introduction of needle fasteners into molded parts from PCM, drilling holes in them with cutting of filler fibers from PCM is required, which will lead to a decrease in the bearing capacity of the joint;

- after creating the connection, it is impossible to replace one of the connected parts (having defects), since the connection is one-piece, since the embedded needle fasteners are completely inside the connected parts, and there is no access to their removal.

The objective of the invention is to develop the design of the docking joints of the panels from a polymer composite material, which would provide a simple manufacture of assembled structural elements, their quick assembly and disassembly, efficient transmission of forces through the mating elements, high bearing capacity and low weight, as well as increasing the threshold of the joint .

This object is achieved in that in the docking connection of the panels of the polymer composite material containing two joined panels, each of which includes the skin and stiffeners, while the first and second panels are connected so that their ends are in close proximity to each other and form the junction line, the stiffeners of the first panel are opposite the stiffeners of the second panel, the first and second panels are partially overlapped by a composite butt plate, one side of which is connected with the first panel, and the other side with the second panel, the composite butt plate partially overlaps the ends of the stiffeners of the first and second panels, according to the invention, the docking connection further comprises three metal plates rigidly joined to the composite butt plate and two panels installed in the joints composite butt plate with panels corresponding in size and shape to the mating zones of the panels, the area of the larger metal plate corresponds to the area of the comp a large butt plate and is equal to the sum of two smaller metal plates fixed on the panels, on one of the surfaces of the metal plates there are rigidly fixed metal needles embedded in the panels, metal sleeves have metal bushings with a height equal to the total thickness of the connected metal plates, while the metal plates smooth surfaces pressed against each other, joined and pulled together with bolts passing through holes made in the connected panels, and metal s sleeve installed in the metal plates.

Metal plates may consist of separate prefabricated sections.

On the surface of metal plates on which metal needles are rigidly fixed, there may be zones free of metal needles.

In the panels to be joined and the composite butt plate, additional metal bushings can be installed located above and below the metal bushings installed in the metal plates and having an inner diameter matching the inner diameter of these bushings, and the outer diameter being smaller than the outer diameter of these bushings.

Throughout the thickness of the package connecting panels can be made through holes in which metal sleeves are installed with bolts tightening this package.

Additional metal bushings installed in the panels to be connected can be connected to the panels and the composite butt plate by means of glue.

In Fig.1 - a typical prefabricated joint of the panel structures of the aircraft through the pad (disassembled condition).

Figure 2 - diagram of a metal composite needle joint reinforced with bushings (section).

Figure 3 is a diagram of a metal composite needle joint reinforced with bushings, options (section).

In FIG. 4 is a diagram of a metal composite needle joint reinforced with bushings, options (section).

In FIG. 5 is a diagram of the location of the needles at the junction in the fastener zone.

The presence of metal plates and metal sleeves can increase the strength of the joint connection to collapse and shear, as well as reduce the stress concentration at the boundaries of the bolt holes. This allows you to reduce the number of fasteners used and, accordingly, to reduce the dimensions, complexity, complexity of manufacturing and the mass of the docking connection.

The presence of needle fasteners makes it possible to increase the strength of the connection between PCM parts (two panels and a composite butt plate) to crush and shear metal plates, as well as reduce the stress concentration at the boundaries of the holes for needle fasteners. This allows you to ensure uniform load distribution between PCM parts and metal plates attached to them, as well as reduce the dimensions and weight of the docking joint.

The presence of metal plates in the form of several blocks or sections makes it possible to simplify the process of assembling a docking joint with large dimensions or surfaces with a large curvature of the parts to be joined.

The presence of free zones on the surface of metal plates on which metal needles are rigidly fixed are designed for drilling additional holes for additional metal bushings in these zones.

The installation of additional metal bushings in the panels to be joined and the composite butt plate allows an additional increase in the strength of the joint compound for collapse and shear, as well as a reduction in the stress concentration at the boundaries of the bolt holes.

To further increase the strength of the joint connection to collapse and shear, additional metal bushings can be connected to the panels and the composite butt plate using glue.

The presence of additional through holes throughout the entire thickness of the package of the docking connection of the panels, into which metal sleeves tightening this package are installed, allows increasing the axial tightening of bolts tightening metal plates pressed by smooth surfaces to each other and reducing the stress concentration at the boundaries of the holes for these bolts , as well as increase the strength of the joint connection to collapse and shear.

The proposed design of the docking joint of panels made of PCM allows you to repeatedly disassemble and reassemble the docking connection, if necessary, to replace damaged parts from the PCM (panels, composite butt plate) with metal plates attached to them.

The docking joint of the PCM panels contains two joined panels 1, 2 and a composite butt plate 3. Panel 1 consists of sheathing 4 and stiffeners 5, panel 2 consists of sheathing 6 and stiffeners 7. The ends of panels 1 and 2 are in close proximity to each other to each other and form a joint line so that the stiffeners 5 of panel 1 are located opposite the stiffeners 7 of panel 2. Panels 1 and 2 in the joint zone are partially overlapped by a composite butt plate 3, while one of its sides is connected to panel 1 and the other - with p Anel 2. Composite butt plate 3 partially overlaps the ends of the stiffeners 5 and 7 of panels 1 and 2. The composite butt plate 3 is connected to panels 1 and 2 using bolts 8. In order to reinforce panels 1, 2 and butt plate 3 in their area connecting to them from the side of the contacting surfaces, metal plates 9, 10, 11 are rigidly attached using metal needles 12, 13, 14, rigidly fixed to one of the surfaces of the metal plates 9, 10, 11. To reinforce the walls of the holes for bolts 8 in the metal plates 9, 10, 11, metal bushings 15 and 16 are installed with a height equal to the total thickness of the corresponding contacting metal plates 9, 10 and 9, 11.

To reinforce the walls of the holes for the bolts 8 in the panels 1, 2 and the composite butt plate 3, additional metal bushings 17 and 18 are installed, located above and below the metal bushings 15 and 16 installed in the metal plates 9, 10 and 11, and having an inner diameter, coinciding with the inner diameter of these bushings, and the outer diameter is smaller than the diameter of these bushings.

To increase the stability of the axial tightening of the bolts 8 and the reinforcement of the walls of the holes in the panels 1, 2, composite butt plate 3 and metal plates 9, 10, 11 through holes through the entire thickness of the connection package of panels 1 and 2 are made through holes in which metal bushings 19 are installed high equal to the total thickness of the connected parts 2, 3, 9, 11, and bolts 8.

With large dimensions or surfaces with a large curvature of the parts to be joined, the metal plates 9, 10, 11 are made of separate prefabricated sections 20, 21, 22, 23.

On the surface of metal plates 9, 10, 11 and PCM parts 1, 2, 3, there are zones 24, free of metal needles, intended for drilling in these zones additional holes for bushings 15, 16, 17, 18.19 and bolts 8.

To increase the strength of the docking joint, additional metal bushings 17 and 18 are connected to the panels and the composite butt pad 3 using glue 25.

The docking connection of PCM panels is assembled in the following order: metal needles 12, 13, 14 are fastened to the metal plates 9, 10, 11 from the side of their interface with the panels from PCM 1, 2 and the composite butt plate 3 by soldering, welding or pressing into pre-drilled holes. After laying out the PCM layers of panels 1, 2 and the composite butt plate 3 in the area of the future docking connection, the corresponding metal plates 9, 10, 11 with metal needles 12, 13, 14 directed inside the PCM layers are superimposed on them. The introduction of needles 12 (13, 14) in the PCM of panels 1, 2 and the butt plate 3 is carried out by applying external pressure to the smooth surface of the metal plate 9 (10, 11). Similarly, plates consisting of several blocks or sections 20, 21, 22, 23 are attached to panels 1, 2 and composite butt plate 3. Next, PCM curing of panels 1, 2 and composite butt plate 3 is carried out together with metal plates 9 connected to them , 10, 11. After curing, panels 1, 2 and composite butt plate 3 (with metal plates 9, 10, 11 attached to them) are installed and fixed on the assembly slip so that the smooth surfaces of metal plates 9, 10, 11 of panels 1 , 2 and comp operating actions cover plate 3 pressed against each other. Then, in panels 1, 2 and composite butt pad 3 in the area of the butt joint in zones 24 free of metal needles 12, 13, 14, holes are drilled together for installing bolts 8. Then, panels 1, 2 are separated from composite butt pad 3, after which, in each part, the holes for the bolts are drilled to the corresponding diameter for the bushings 15, 16 (if necessary, for the bushings 17, 18, 19). Corresponding bushings are installed in the holes obtained (if necessary, bushings 17, 18 are installed in panels 1, 2 and a composite butt pad 3 for glue 25). After installing the bushings, the panels 1, 2 and the composite butt plate 3 are re-installed and fixed on the assembly slide and finally tightened with bolts 8. If it is necessary to replace any part from the PCM (for example, if it is destroyed), the joint can be disassembled by untwisting bolts 8 and removal of sleeves 15, 16 (17, 18, 19). In this case, not only the PCM part is replaced, but also the metal plate attached to it.

The assembly procedure for a docking joint with a new PCM part is similar to that described above with the only difference being that in the remaining unsubstituted parts, the holes for bolts 8 and bushings 15, 16 (17, 18, 19) will be guides for drilling the corresponding holes in the new part.

The docking connection of panels from PCM works as follows. The docking connection is designed to transfer the load from the panel 1 to the panel 2 through the composite butt plate 3. The load transfer from the panel 1 to the composite butt plate 3 is as follows: the load perceived by the panel 1 is distributed partially to the metal plate 10 through metal needles 13 and partially directly to bolts 8 (through panels 1 to bushings 17 and glue 25, if any). Further, through the bushings 15 (17, 18, 19) and the bolts 8, the load is transferred partially to the metal plate 9 of the composite butt plate 3 and partially directly to the composite butt plate 3 (through the sleeve 18 or 19, adhesive 25, if any). Then, from the metal plate 9, through the metal needles 12, the load is completely distributed to the composite butt plate 3. Similarly, the load is transferred from the composite butt plate 3 to the panel 2.

The load between the panels 1, 2, the composite butt plate 3 and the metal plates 9, 10, 11 is redistributed in direct proportion to the areas of their cross section in the joint zone and the longitudinal elastic modules of the materials from which they are made.

Claims (6)

1. Docking connection of panels made of a polymer composite material, containing two joined panels, each of which includes a casing and stiffeners, while the first and second panels are connected so that their ends are in close proximity to each other and form a joint line, stiffeners the first panel are located opposite the stiffeners of the second panel, the first and second panels partially overlap the composite butt plate, one side of which is connected to the first panel, and the other side is from W By means of a panel, the composite butt plate partially overlaps the ends of the stiffeners of the first and second panels, characterized in that the docking connection further comprises three metal plates rigidly joined to the composite butt plate and two panels installed in the joint areas of the composite butt plate with the panels, in size and the shape corresponding to the mating zones of the panels, the area of the larger metal plate corresponds to the area of the composite butt plate and is equal to the sum of two smaller met On the surface of the metal plates fixed on the panels, one of the surfaces of the metal plates has rigidly fixed metal needles embedded in the panels, metal sleeves have metal bushings with a height equal to the total thickness of the connected metal plates, while the metal plates are pressed against each other by smooth surfaces, joined and pulled together with bolts passing through holes made in the panels to be connected, and bushings mounted in metal plates. 2. The joining connection of the panels of the polymer composite material according to claim 1, characterized in that the metal plates consist of separate prefabricated sections. 3. The joining connection of the panels of the polymer composite material according to any one of claims 1 to 2, characterized in that on the surface of the metal plates on which the metal needles are rigidly fixed, there are zones free of needles. 4. Docking connection of panels made of a polymer composite material according to claim 1, characterized in that through the entire thickness of the package connecting panels made through holes in which metal sleeves are installed with bolts tightening this package. 5. The joint of the panels of the polymer composite material according to claim 1, characterized in that in the panels to be joined and the composite butt plate additional metal bushings are installed, located above and below the metal bushings installed in the metal plates, and having an inner diameter matching the inner diameter the diameter of these bushings, and the outer diameter is less than the outer diameter of these bushings. 6. The joint of the panels of the polymer composite material according to claim 5, characterized in that the additional metal bushings are connected to the panels and the composite butt plate by means of glue.

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