RU2807801C1 - Power mesh frame of a panel or shell made of laminated composite materials - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: used in aviation, space, shipbuilding and automotive production, as well as in construction. According to the invention, a power mesh frame 1 of a panel or shell made of layered composite materials, consisting of intersecting, made in one piece, inclined 2, 3 and transverse 4 ribs, formed from layers of systems of intersecting tapes (24) repeating through the thickness of the frame, and covering them, with respectively oriented unidirectional threads in them, layers of outer skin (16), or without them, fastened with a polymeric binder, is made variable on the surface and/or in local areas of rigidity due to the use of various options for changing the parameters of the frame: changing the location of the ribs 2, 9, use of shortened ribs 5, 6, 8, 12, 13, 14, 15, 20 or ribs of variable width 7, 11 and height 23, 35, changing the angle of the rib along its length 21, changing the location of the tapes 25, 26, 29 that make up the rib of 25, 26, 29, 30, 32, 33 tapes.

EFFECT: increasing the weight perfection of panels and shells with load-bearing mesh frames by changing the rigidity of the frame in accordance with the acting variables on the surface or in the local area of the loads.

18 cl, 9 dwg

Description

The invention relates to the field of mechanical engineering and can be used in aviation, space, shipbuilding and automotive technology, as well as in construction.

Shells and panels with load-bearing mesh frames are widely used in various fields of mechanical engineering and construction. One such area is the aviation industry, in which shells and panels made of composite materials are used as elements of the outer skin of aircraft: fuselage, wings, and tail.

Known RETINA ROTATION according to RU 2153419 C1, publ. 07/27/2000, containing a plurality of intersecting spiral and annular stiffeners and covering layers of outer skin with intersecting unidirectional threads respectively oriented in them, held together by a polymer binder.

Known PANEL OF LAYERED COMPOSITE MATERIALS according to RU 2518519 C2, publ. 06/10/2014, consisting of a power set of intersecting ribs containing layers of unidirectional high-strength (high-modulus) threads bonded with a polymer binder

Known MESH SHELL OF ROTATION FROM COMPOSITE MATERIALS according to RU 2392122 C1, publ. 06/20/2010, formed from layers of systems of intersecting spiral, longitudinal and annular tapes of unidirectional threads held together by a polymer binder, repeating along the thickness of the shell wall, forming spiral, annular, longitudinal and additional ribs, in which the additional ribs are oriented in the longitudinal direction, while they shorter than the length of the generatrix and unevenly distributed along the length and perimeter.

There are known designs of mesh structures consisting of intersecting ribs made by winding a continuous tape of unidirectional threads impregnated with a binder. (Vasiliev V.V. Mechanics of structures made of composite materials. - M.: Mashinostroenie, 1988. - 272 p.).

All of the above structures of mesh frames consist of rectilinear (in the case of a shell, rectilinear on a development) constant cross-section of intersecting ribs, distributed over the surface with a constant pitch and fastened together at intersections (nodes).

Straight-line (for shells - on the surface development) ribs with constant parameters: width, height, determined by the boundaries of the frame, length, angle and spacing, are standard (typical) for such structures.

The ribs consist of a unidirectional continuous reinforcing material (threads) impregnated with a binder, located along the height of the ribs in layers (ribbons).

The minimum structural element of a mesh frame is a cell formed by two pairs of intersecting ribs.

The defining parameters of the rib are: width, height, length, curvature in plan, angle and pitch that make up the rib of the tape of reinforcing material.

The constancy of the parameters of the ribs along the length and the uniformity of their location on the surface ensures the constancy of the mechanical characteristics (strength, rigidity) in the frame, which leads to the production of equal-strength structures (panels, shells) of minimal weight under constant loads.

But there are no fewer structures that are subject to variable loads distributed over the surface and/or in local zones, for example, wind, inertial, aerodynamic. In addition, many structures require local areas of increased rigidity to form places for attaching additional parts and assemblies, framing various holes and hatches, etc.

To meet such requirements while maintaining high mass efficiency, structures and load-bearing frames, including variable surface and/or local area strength and rigidity, are required.

The technical solution for patent RU 2392122 C1 proposes strengthening the rib frame by using (positioning) additional shortened longitudinal ribs. This narrowly targeted solution provides an increase only in longitudinal strength (stiffness). In this case, the problem is solved through the use of additional ribs to the general power system, which affects the mass and labor intensity.

The mesh shell made of composite materials according to patent RU 2153419 is closest to the claimed one in terms of technical essence and achieved result and was chosen as the closest analogue (prototype).

The technical problem to be solved by the invention is the creation of a structure for a load-bearing mesh frame of a panel or shell made of composite materials, which provides increased performance and efficiency by obtaining a load-bearing frame design of variable stiffness, ensuring high reliability under variable loads.

The technical result that can be obtained by using the invention is to expand the scope of applicability of the power mesh frame of a panel or shell made of layered composite materials due to the optimal distribution of strength and rigidity in the frame structure, while maintaining the necessary reliability, under the influence of distributed and/or local variables loads, increasing the operational and economic efficiency of panel and shell structures with the claimed load-bearing mesh frame due to the possibility of obtaining structures of lower mass and cost, simplifying the technology and reducing the labor intensity of manufacturing through the use of existing technological methods and equipment when creating a frame of variable stiffness.

The technical problem is solved, and the technical result is achieved by the fact that in the power mesh frame of a panel or shell made of layered composite materials, consisting of intersecting, one-piece, inclined and transverse ribs formed from layers of intersecting tape systems repeated along the thickness of the frame, and covering them, with respectively oriented unidirectional threads, layers of outer skin, or without them, fastened with a polymer binder, according to the invention, at least one rib of the frame is made atypical, partially or completely, non-coinciding with the other ribs in its geometric dimensions and/or location, forming a variable and/or in at least one area, a locally variable change in the current rigidity of the frame in one or more directions, and in particular cases of the invention, atypical ribs are made of at least one group, with divergent angles relative to the axes of the frame, but not intersecting among themselves, the angles of arrangement of atypical ribs in a group change monotonically from edge to edge, atypical ribs are made of two mirror-symmetrical groups with respect to an arbitrary coordinate, for example, longitudinal, with identically changing angles of arrangement in each, an atypical edge is made with at least one step changing angle of location at the intersection with another rib, the atypical rib is made shorter than the possible length in the frame, in accordance with its location, with a connection and/or intersection with the ribs of the frame, short atypical ribs are located in a group in a local area with mutual connection at the ends and/or intersections, at least two ribs are connected into one with a change in the angle of location at the connection node, the ribs before and after the connection are made with the same cross-sectional area, an atypical rib is made with a variable height and/or width along the length, a variable rib height is made by changing the the length of the number of tapes composing it, the number of tapes composing an edge monotonically decreases along the length of the edge, at least one component of an atypical edge a continuous tape passes from one edge to another with a turn at the node of their connection or intersection, the intersection nodes of the ribs with the tapes deployed in them are distributed along frame in accordance with the required change in its local and/or overall rigidity, the intersection nodes of the ribs with the tapes deployed in them are located in at least one cross section of the frame; in the cross section, the location step of the intersection nodes of the ribs with the tapes deployed in them varies from section to section , the constituent edges of the tape are made with at least one transverse clearance, the constituent edges of the tape are made to cover at least one embedded element.

The features of the claimed frame that are distinctive from the prototype are the following:

a) features that ensure the achievement of a technical result in all cases covered by the requested scope of legal protection:

- at least one rib of the frame is made atypical, partially or completely, and does not coincide with the other ribs in its geometric dimensions and/or location,

- forming a variable and/or in at least one area a locally variable change in the current rigidity of the frame in one or more directions.

b) features characterizing the invention in particular cases:

- atypical ribs are made of at least one group, with divergent angles relative to the frame axes, but not intersecting with each other,

- the angles of location of atypical edges in the group vary monotonically from edge to edge,

- atypical ribs are made of two groups that are mirror-symmetrical to each other with respect to an arbitrary coordinate, for example, longitudinal, with equally varying angles of arrangement in each.

- an atypical rib is made with at least one stepwise changing angle of location at the intersection with another rib,

- the atypical rib is made shorter than the possible length in the frame, in accordance with its location, with a connection and/or intersection with the frame ribs,

- short atypical ribs are located in a group in a local area with mutual connection at the ends and/or intersections,

- at least two edges are connected into one with a change in the angle of location at the connection node,

- the ribs before and after the connection are made with the same cross-sectional area,

- an atypical rib is made with a variable height and/or width along the length,

- the variable height of the rib is made by changing the number of its constituent strips along the length,

- the number of tapes composing the edge monotonically decreases along the length of the edge,

- at least one component of an atypical edge continuous tape passes from one edge to another with a turn at the node of their connection or intersection,

- the intersection points of the ribs with the tapes deployed in them are distributed along the frame in accordance with the required change in its local and/or overall rigidity,

- the intersection points of the ribs with the tapes deployed in them are located in at least one cross section of the frame,

- in the cross section, the spacing of the nodes of intersection of the ribs with the tapes deployed in them varies from section to section,

- the tape rib components are made with at least one transverse clearance,

- the components of the edge of the tape are made to cover at least one embedded element.

These distinctive features, each individually and collectively, are aimed at achieving the stated result and are essential. In the prior art, the set of known and distinctive features presented in the claims is not known and, therefore, the invention meets the “novelty” criterion.

The stated result is achieved by the fact that in the proposed design of a power mesh frame of a panel or shell made of layered composite materials, the location of the ribs and/or their geometry, in contrast to known solutions, are partially or completely variable along the dimensional directions of the frame, which ensures variable rigidity of the structure in the required directions and areas. The use of various options for atypical ribs: changing the location of the ribs, using ribs of variable width, height or length, changing the angle of the fin along its length, changing the location of the tapes that make up the ribs - allows in each specific case to use the most optimal solution to obtain maximum efficiency in terms of mass and manufacturability and efficiency.

The proposed power mesh frame represents a single monolithic structure, which ensures high strength and reliability, combines in one technological process the production of a shell or panel of variable stiffness, which reduces the range of technological equipment and reduces the cost of production, reduces the labor intensity of manufacturing and helps improve the quality of thin-walled power structures, such as the fuselage , wing or empennage of an aircraft.

A similar design can be used in the manufacture of hull cladding in the aviation, space, shipbuilding, automotive industries, and in construction, for example, as bridge panels, building slabs, etc.

The design of the panel frame or shell according to the proposed technical solution is industrially feasible using known means and methods and ensures the implementation of the specified purpose.

The invention is illustrated by a description of specific, but not limiting, examples of implementation and the accompanying drawings.

In fig. Figure 1 shows a panel frame with a group of atypical ribs with varying angles.

In fig. Figure 2 shows a panel frame with two groups of atypical ribs with varying angles.

In fig. Figure 3 shows a cross section of the panel.

In fig. Figure 4 shows the load-bearing frame of the shell with connecting atypical ribs.

In fig. Figure 5 shows a diagram of the load-bearing frame of the shell (panel) with connecting and bending atypical ribs.

In fig. Figure 6 shows a diagram of changing the location of the tapes at the edge intersection nodes.

In fig. Figure 7 shows a diagram of the arrangement of the tapes when connecting (combining) the ribs.

In fig. Figure 8 shows a diagram of the arrangement of tapes when connecting the ribs.

In fig. Figure 9 shows a view of a variable height rib.

Power mesh frame 1 panel or shell (Fig. 1) made of layered composite materials, consisting of intersecting, made in one piece, inclined 2, 3 and transverse 4 ribs, formed from layers of intersecting tape systems repeated throughout the thickness of the frame, and a layered layer covering them outer skin bonded with a polymer binder.

In the frame, at least one edge of the frame is made atypical, partially or completely, inconsistent with the other ribs in its geometric dimensions and/or location, forming a variable and/or in at least one area a locally variable change in the current rigidity of the frame in one or more directions.

In a particular case of execution, atypical ribs can be made of at least one group 2, with divergent angles of location (angles of inclination) relative to the axes of the frame, but not intersecting with each other.

The angles of location of atypical edges 2 in a group can vary monotonically from edge to edge, i.e. each next edge can be rotated relative to the previous one by a certain constant angle - angle α.

As a result, along the length of the rib (along the length of the frame), the distance between the ribs increases and the angle of location relative to the longitudinal coordinate of the panel increases for each subsequent rib. Changing each of these parameters leads to a change in the rigidity of the frame; the effect of changing the two factors is summed up. In this case, the change in rigidity also occurs in the transverse direction.

Atypical ribs can be made of two groups 9 and 10, mirror-symmetrical to each other, relative to an arbitrary coordinate, for example, longitudinal (Fig. 2). In both groups, each subsequent edge is rotated relative to the previous one by a constant angle β. In this case, the magnitude of the change in rigidity increases, but the distribution over the surface becomes symmetrical relative to the longitudinal axis, in contrast to the previous option.

The rigidity in both options varies smoothly along the longitudinal and transverse coordinates of the frame over the entire length and width of the frame.

The power mesh frame 1 can be made with or without outer skin 16 (Fig. 3).

Atypical ribs 21 can be made with at least one stepwise changing angle of location at the intersection node 22 with another rib (Fig. 5).

As a result, the geometric parameters of the frame change, as when the entire rib is rotated, but within one cell, i.e. in this case, the rigidity of the rib, and accordingly the entire frame, changes with a step of cell size.

The view of the frame in Fig. 5 equally corresponds to the panel frame and the frame of the cylindrical shell with the presented surface development.

In a particular case of execution, atypical ribs 5, 6, 8, 12, 13, 14, 15, 20 can be made shorter than their possible length in the frame, in accordance with their location, with a connection and/or intersection with the frame ribs, increasing the rigidity of the frame in a limited area. Short atypical ribs 5 (Fig. 1), 12, 13, 14, 15 (Fig. 2) are located in a group in a local area with mutual connection at the ends and/or intersections. Ribs 5 provide reinforcement of the frame in the area of the hole (hatch, window), ribs 6 (Fig. 1) and 20 (Fig. 5) increase uniform rigidity over a given length of the frame, ribs 8 (Fig. 1) in the form of jumpers connect two ribs , ribs 12, 13 and 14, 15 in the form of lattice increase the local rigidity of the frame. In this case, the ribs in the lattices according to the last two options can be arbitrarily oriented between themselves and the frame and differ from each other, for example, in the shape of the cross section.

An atypical rib can be made with a variable length width of 7 (Fig. 1), 11 (Fig. 2). In this case, the expansion 7 can be performed by transferring continuous tapes from the jumpers 8 and back.

At least two ribs 17 can be connected (combined) into one 18 with a change in the angle of location at the connection node (Fig. 4). At the same time, the number of ribs decreases and the spacing of their location increases. In the case of frames with a decreasing width along the length (circumference length for shells), the increase in the step from the connection (union) can be offset by a decrease in the step due to a decrease in the transverse size, which, together with a decrease in the number of ribs, makes it possible to smoothly reduce the rigidity of the frame in accordance with changes in the design metrics.

When connecting two ribs 17, the cross-sectional area of the resulting (unifying) rib 18, provided that the continuity of the reinforcing material (tape) is maintained, can vary from the sum of the cross-sectional areas of the converging ribs to zero (absence) of the combining rib due to the appropriate distribution of the tapes that make up the rib.

In a particular case of execution, part of the tapes 29 that make up the edge (Fig. 7) can unfold and move from one converging edge to another, and the rest of the tapes 30 go into the connecting edge.

By varying the number of tapes 29 and 30, it is possible to create converging and connecting ribs 28 of different sections and rigidities.

As an embodiment, transverse ribs 19 can be combined (branched) to form a more dense lattice in a limited transverse (circumferential) zone of the frame.

Changing the angle of location can be an independent solution for the entire ribs 21 or used for individual tapes 25, 26 when changing the parameter of ribs 23, tapes 29 for ribs 28, tapes 32, 33 for ribs 31.

In a particular case of execution, at least one component of the atypical rib 23, a continuous tape 25 or 26 (Fig. 6), 32 or 33 (Fig. 8) can move from one rib to another with a turn at the node of their connection or intersection.

When turning according to the version of belts 25 and 26, the height of the rib 23 behind the intersection node, and accordingly the rigidity, decreases.

The intersection points of the ribs with the tapes 25 or 26 deployed in them can be located in at least one cross section of the frame, which leads to a decrease in the rigidity of the frame beyond the section. Nodes with tapes deployed in them from section to section and even in the same section can be located with different (variable) pitches, for example, as tapes 25 and 26, which provides an additional opportunity to change the rigidity of the frame in the longitudinal and transverse directions. By changing the ratio of the number of deployed tapes 25, 26 and the remaining 24, you can change the rigidity of the ribs, and accordingly the frame, according to the necessary law.

There may be several cross sections with tapes 25 and/or 26 deployed in them along the length of the frame, and the spacing of the nodes with deployed tapes in each of them may differ from the other sections.

The intersection nodes of the ribs with the tapes 25, 26 deployed in them can be distributed over the frame in accordance with the required change in its local and/or overall rigidity.

In another variant of a particular case of execution, the components of the edges of the tape 32, 33 can be deployed in the direction of the transverse edge at the nodes of their connection. The height of the connected ribs 31 is determined by the number of their constituent tapes 32, 33, 34 and can be changed by changing their ratio.

By changing the location of the tapes at the nodes of intersections and connections, you can change the rigidity of the frame according to any arbitrary law, placing continuous tapes along the required curve 27 (Fig. 5). In this case, tapes with bends can be located on existing frame tapes (on top of an existing rib) or alternate with the latter, increasing the local height of the ribs, can be located next to existing ribs, increasing their local width, or a combination of the two indicated options can be used.

Changing the direction of arrangement and the transition of individual strips from one rib to another ensures reliable fastening of the frame elements, ensuring its solidity. With the use of such transitions, all elements become mechanically equal in a system of intersecting and connecting ribs.

In a particular case of execution, an atypical rib 35 (Fig. 9) can be made with a variable height along the length by changing the number of tapes 36 that make it up along the length. The rib can be made of smoothly decreasing stiffness due to a monotonous decrease in the number of tapes that make up the rib along the length of the rib.

The tapes 36 that make up the rib 35 can be made with at least one transverse clearance 37, which makes it possible to increase the bending rigidity of the rib by increasing the height, while maintaining mass.

The tapes 36 that make up the rib 35 can be made to cover at least one embedded element 38. Fastening the embedded element in several adjacent ribs makes it possible to increase the local rigidity of the frame. At the same time, such an embedded element can be used to attach the necessary parts of the overall structure to the frame.

The claimed technical solution makes it possible to create mesh frames with any distribution of rigidity through the use of ribs with variable geometry (width, height, length, curvature in plan), angle and pitch of arrangement, number and directions of arrangement of the continuous strips that make up the ribs.

An experimental test carried out at a serial enterprise using industrial equipment confirmed the high strength, reliability and operational efficiency of the proposed options for the load-bearing mesh frame.

Claims (18)

1. Power mesh frame of a panel or shell made of layered composite materials, consisting of intersecting, made in one piece, inclined and transverse ribs, formed from layers of systems of intersecting tapes repeated throughout the thickness of the frame, and covering them, with unidirectional threads oriented accordingly in them, layers of outer cladding, or without them, bonded with a polymer binder, characterized in that at least one rib of the frame is made atypical, partially or completely inconsistent with the other ribs in its geometric dimensions and/or location, forming a variable and/or in at least one area locally -variable change in the current rigidity of the frame in one or more directions. 2. The frame according to claim 1, characterized in that the atypical ribs are made of at least one group, with divergent angles relative to the axes of the frame, but not intersecting with each other. 3. Frame according to claim 2, characterized in that the angles of location of atypical ribs in the group vary monotonically from edge to edge. 4. The frame according to claim 1, characterized in that the atypical ribs are made of two groups that are mirror-symmetrical to each other with respect to an arbitrary coordinate, for example, longitudinal, with equally varying angles of arrangement in each. 5. The frame according to claim 1, characterized in that the atypical rib is made with at least one stepwise changing angle at the intersection with another rib. 6. Frame according to claim 1, characterized in that the atypical rib is made shorter than the possible length in the frame, in accordance with its location, with a connection and/or intersection with the ribs of the frame. 7. Caracas according to claim 6, characterized in that the short atypical ribs are located in a group in a local area with mutual connection at the ends and/or intersections. 8. Frame according to claim 1, characterized in that at least two ribs are connected into one with a change in the angle of location at the connection node. 9. Frame according to claim 8, characterized in that the ribs before and after the connection are made with the same cross-sectional area. 10. Frame according to claim 1, characterized in that the atypical rib is made with a variable height and/or width along the length. 11. Frame according to claim 10, characterized in that the variable height of the rib is made by changing the number of its constituent strips along the length. 12. Frame according to claim 11, characterized in that the number of tapes constituting the rib decreases monotonically along the length of the rib. 13. Frame according to paragraphs. 1, 6, 7, 8, characterized in that at least one component of the atypical edge continuous tape passes from one edge to another with a turn at the node of their connection or intersection. 14. The frame according to claim 13, characterized in that the intersection nodes of the ribs with the tapes deployed in them are distributed over the frame in accordance with the required change in its local and/or overall rigidity. 15. The frame according to claim 13, characterized in that the intersection points of the ribs with the tapes deployed in them are located in at least one cross section of the frame. 16. Frame according to claim 15, characterized in that in the cross section the step of location of the nodes of intersection of the ribs with the tapes deployed in them varies from section to section. 17. Frame according to paragraphs. 1, 11, characterized in that the tape rib components are made with at least one transverse clearance. 18. Frame according to paragraphs. 1, 11, characterized in that the components of the edge of the tape are made to cover at least one embedded element.

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