FR2488390A1 - Mfr. of explosive-charged warhead - uses windings of mineral fibres orientated at zero and right angles to axis - Google Patents

Abstract

The method manufactures round components charged with explosive, particularly for warheads of rockets and other missiles, by rotation of a guide line round the component axis. This guide line is straight, curved or interrupted and under radial pressure. It uses two or more superimposed layers of fibrous windings, typically of mineral fibre. The fibres in one layer (1) are nearly at 0 deg. to the major axis of the component, while those of the other one (2) are nearly at 90 deg. to it. Where the interior shape is complex, preliminary partial windings can be used, over which the external ones are positioned.

Description

The development of new fibers, and the evolution of technologies for implementing composite materials using these fibers as the main constituent element of a construction that is both light and solid, makes it possible to replace many metallic components in the production of structural structures. projectiles and missiles
However, these different composite materials do not systematically satisfy all uses, and they require special provisions both in the choice of basic components (fibers and resins, for example), as in the technical design of structures and in the technology of Implementation.

 Structural elements with thin walls, like the envelopes of anti-tank projectiles, for example, are subjected to stresses composed of axial compression and radial pressure. The very principle of the behavior of a filament winding does not allow a direct answer to the problem posed by the existence of these constraints.

 The present invention provides a solution to this problem by constituting the (thin) envelope by at least two superimposed layers of different filament windings, organized to absorb the axial compression forces, on the one hand, and possibly the radial pressure forces. , on the other hand. There is thus obtained, according to the invention, a light and solid construction, specifically more efficient than an equivalent metallic construction would be.

 Without departing from the scope of the invention, the filamentary construction may have shoulders, threads or bosses, without this requiring subsequent machining operations.

It will be recalled that a piece of wound fibers, for example a hollow cylinder, subjected to a compressive force along its longitudinal axis, requires an arrangement of the fibers such that the axis of these fibers makes an angle
drank as small as possible with the axis of this effort.

 However, this compression force induces, for certain critical values, buckling forces in the part, hence bending forces in the fibers, which is unfavorable.

 It is therefore necessary to circumferentially maintain the axial ply of the fibers so that the latter work in compression. This is precisely what the process according to the invention allows.

 The attached drawing shows a nonlimiting example of an embodiment of this type of part according to the invention.

 It is clearly stated, however, that this is only an example, that all other modes of construction, shapes, proportions, arrangements, etc., can also be used without departing from the scope of the invention.

 It is also recalled that, if the example treated relates to a projectile with a hollow charge, the invention also applies to all other projectiles, bombs, shells, etc.

 The single Figure of the drawing represents a view in longitudinal half-section of an explosive projectile which consists of an envelope (A) according to the invention, in complex wound (fiberglass, dellkevlar "carbon or other), d '' a hollow charge coating (B), and an explosive charge (C).

 According to the invention, to produce the envelope (A), a spool is wound on a mandrel, or on another part of the subassembly to be formed, first of all a first series of layers of fibers (1) carbon, nonlimiting example), according to a winding angle 1> (as close as possible to O "(to be defined in each case, according to the intensity of the effort, the shape of the part, etc.), and this ply is radially reinforced by the winding of a second series of plies of fibers (2) at a winding angle $ as close as possible to 90 "(also to be defined in each case, depending on the width of plies and the shape of the part).

 According to the invention, the internal shape, which must be of revolution, can be generated, by rotation about its axis of revolution XX ', by a straight line parallel or not to this axis, by certain curves or certain broken lines (3) .

 In the case of certain broken lines, the shoulders can be produced, according to the invention, by prior winding of a series of plies of fibers (4), at a winding angle g as close as possible to 90 "( to be defined in each case, depending on the width of the plies and the shape of the shoulder).

These preliminary windings (4) ensure, by prior filling, good transmission of forces to the fibers of the first winding (1), of angle Q (
In the case where it is desired to produce a part comprising a thread (5) or boss or bulge, annular or not (6), these are produced, according to the invention, by overmolding after the execution of the double winding ( 1) - (2), and before curing the part.

Claims (4)

 1 - Process for the production of revolution parts loaded with explosives, such as, in particular, charge bodies, military head envelopes, rockets or missiles, generated by rotation, around the axis of revolution, of a parallel director or not parallel to this axis, the directrix being a straight line or a curved line or a broken line, working in compression and in radial pressure, characterized by the use of at least two superposed layers of filament windings made up of fibers such as fibers mineral, the fibers of one of the layers (1) making, with the long axis of the part of revolution, an angle close to 0, the fibers of the other layer (2), or of the other layers, making with this axis an angle close to 90 ".  2 - Process for producing parts according to claim 1, characterized in that, in the case of a complex interior shape, such as a broken line, partial preliminary windings are used, around which said superimposed windings are then made.  3 - A method of producing parts according to any one of claims 1 and 2, characterized in that bosses, threads, bulges, annular or not, that the part must include are added by overmolding after the execution of the superimposed windings, and before polymerization of the part.  4 - Revolutionary parts loaded with explosives, such as, in particular, charge bodies, military head envelopes, rockets or missiles, produced in accordance with the method according to any one of the preceding claims.