RU2270393C1 - Tube-envelope made from composite material - Google Patents

Abstract

FIELD: manufacture of parts from composite materials having form of bodies of revolution; manufacture of cases and compartments of flying vehicles; rocketry and aeronautical engineering.

SUBSTANCE: proposed tube-envelope made from composite material has wall of spatial-slotted structure formed by spiral and circular tapes alternating to each other and wound discretely in cross-like manner; tapes are fastened together in cross lines and are separated by slots in inter-unit gaps. Tapes forming structure are shifted relative to one another in height of wall and slots between them have varying magnitude and are chaotically distributed over wall structure.

EFFECT: enhanced reliability of structure due to enhanced strength and rigidity.

2 cl, 3 dwg

Description

The invention relates to the creation of products from composite materials (CM), in particular products having the form of bodies of revolution, and can be used in the manufacture of bodies and compartments of aircraft used in rocket and aviation technology.

The solution to the problems of reducing the mass of shell structures made of KM led to the creation of lightweight, strong and rigid pipe shell structures with monolithic ribs that form the basis of their structure (RU Patent No. 2149761, class B 32 V 1/00, 3/12; B 29 C 53/56, publ. 27.05.2000, bull. No. 15; RU patent No. 2083371, class B 32 3/12, publ. 1986).

The monolithicity of the ribs due to an excess of binder in them prevents the weight loss of known pipe shells. The complexity and duration of the manufacturing process using special equipment (mandrels with grooves) make well-known designs expensive in terms of labor, money and time.

A known design of the pipe shell of KM, the wall of which is made with a spatially slit structure of ribbons of fibrous material wound discretely and crosswise; the tapes are fastened with a binder only at the nodes of mutual crosshairs, and between the crosshairs they are not fastened together and are separated by through slots (RU patent No. 2215227, class F 16 L 9/12, 47/00, publ. October 27, 2003, bull. No. 30).

This known design is lighter than the above due to the numerous slots between its tapes, eliminating excess binder. It is easy to manufacture, does not require special equipment for production; it is made by winding on a smooth (without grooves) surface of the mandrel. However, it is unstable, has low characteristics of strength and stiffness. Strict laying of spiral ribbons on top of each other with the formation of a strict ribbed structure provides through holes that are equally located in all ribs along the wall thickness, but it is this that causes the instability of the structure, its low strength and rigidity.

The sheath pipe according to RU patent No. 2215227 is the closest in technical essence to the claimed one and is selected as the closest analogue (prototype).

The technical problem to which the invention is directed is the development of the design of the pipe-shell, which would be as light as its closest analogue, but more effective in operation.

The technical result that can be achieved by using the invention is to increase the reliability of the structure by increasing its strength and rigidity.

To solve the problem with the achievement of the specified result in a well-known pipe sheath of KM containing a wall of a spatially slit structure formed by discrete and cross-wound ribbons of fibrous material, fastened with a polymer binder at the nodes of their mutual crosshairs and separated by slots in the interstitial spaces, according to the invention the tapes of this structure are offset relative to each other along the height of the wall, and the gaps between them are formed of variable size and randomly distributed over the structure Tenkai, wherein said spatial-gap structure is formed by the spiral wall and the annular belts placed alternately in relation to each other.

Distinctive features of the claimed pipe-shell are the following features:

- the displacement of the tapes of the spatial-slot structure relative to each other along the height of the wall;

- the formation of gaps between the tapes in the interstitial spaces of variable size;

- chaotic distribution of cracks in the structure of the wall;

- the formation of the aforementioned structure with spiral and annular ribbons placed alternately relative to each other.

These signs are significant, since each of them is aimed at achieving the claimed technical result in accordance with the task. In the technical solutions of the prior art, their use is not found.

The claimed pipe-shell is made with a change in the geometry of the surface after laying the tapes in any of the directions due to the displacement of each subsequent tape in one direction relative to the previous tape in the same direction. This has achieved the production of a ribless, or pseudo-rib, structure as more stable, durable and rigid in comparison with the structure of the prototype. The position of the tapes of one direction relative to each other is fixed at the nodes of their intersections with the tapes of another direction. The mismatch of the tapes along the height of the wall, taking into account the fact that its collection requires at least three tapes in height in each direction, ensures the formation of inter-nodal spaces of randomly sized non-through gaps. The presence of slots provides a small mass under compressive forces in the pipe-shell.

The claimed pipe-shell with a wall of a spatially slotted structure can be made of any sets of discrete and cross-wound tapes, for example spiral with axial or spiral with ring. The best results in strength and stiffness are achieved in a pipe-shell made of alternating spiral and ring bands. It is such a pipe-shell is described below as an example of execution of the invention.

The invention is illustrated in figures 1-3. Figure 1 presents a General view of the claimed pipe-shell, figure 2 is a view a of figure 1, figure 3 is a section bB of figure 2.

The pipe sheath made of KM (FIGS. 1, 2) contains a wall 1 of a spatially slit structure formed by discrete and cross-wound spiral 2 and annular 3 ribbons of fibrous material placed alternately relative to each other. Tapes 2 and 3 are fastened together by a polymer binder in nodes 4 of their crosshairs and are separated by slots 5 in the interstitial spaces (figure 3).

Each subsequent tape 2 (or 3) with respect to the same previous tape 2 (or 3) is shifted in one direction or another along the height of the wall 1 so that the slots 5 between any adjacent tapes 2 (or 3) practically do not coincide in size or at their location.

The pipe-shell is made on standard equipment by winding on a smooth surface of the mandrel. Polymeric materials are used as a binder, unidirectional tows are used as the material of tapes: carbon, organic, glass or any other suitable for this purpose. It is possible to use a partially cured tape consisting of profiled unidirectional strands impregnated with a binder with a cross-sectional profile in the form of a circle, rectangle, ellipse, etc.

The claimed pipe-shell may be externally and / or internally made integrally with it or separately wound sheathing.

Wall thickness, laying angles of spiral tapes, the distance between the turns depend on the specific task and are determined by calculation.

The proposed pipe shell is used as a structural element of the compartment of the aircraft. Its advantages: high strength and rigidity with minimal weight, manufacturability, were confirmed by tests for the action of axial compressive and tensile loads.

Claims (2)

1. A sheath pipe made of a composite material containing a wall of a spatially slit structure formed by discrete and cross-wound ribbons of fibrous material, fastened with a polymer binder at the nodes of their mutual crosshairs and separated by slots in the interstitial spaces, characterized in that the tapes of this structure are offset relative to each other along the height of the wall, and the gaps between them are formed of variable size and randomly distributed over the wall structure. 2. The pipe-shell according to claim 1, characterized in that the spatially slotted structure of its wall is formed by spiral and annular tapes placed alternately relative to each other.

Images