AU2003264628A1

AU2003264628A1 - Jet-forming Charge

Info

Publication number: AU2003264628A1
Application number: AU2003264628A
Authority: AU
Inventors: Joel Ferron; Henri Ropars
Original assignee: TDA Armements SAS
Current assignee: TDA Armements SAS
Priority date: 2002-12-13
Filing date: 2003-12-01
Publication date: 2004-07-01
Anticipated expiration: 2023-12-01
Also published as: EP1429107B1; FR2848657A1; AU2003264628B2; FR2848657B1; DE60331038D1; EP1429107A1

Description

S&F Ref: 657980

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: TDA Armements SAS 45 rue de villiers 92526 Neuilly Sur Seine France Henri Ropars Joel Ferron Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Jet-forming Charge The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c 1 Jet-forming charge The present invention relates to a jet-forming charge.

It applies in particular to charges placed in munitions which work by overflying their objective.

Jet-forming charges (also known by the name of shaped charges or explosively formed penetrators (EFPs)) are explosive warheads containing a liner set in motion by the detonation of an explosive warhead charge placed in a confinement (also known by the name of envelope) generally cylindrical and made of metal. The liner deforms to form a jet, projected at a speed of the order of 2000 m/s towards a target. Such charges are used to form the warheads of munitions. They are also used in industry (boring, mining works, etc.). The general operating principles of the charges are described in the document "Fundamentals of Shaped Charges" by W.P. Walters and J.A. Zukas (Publisher: CMCPress, ISBN: 0-471-62172-2).

Armoured targets are most particularly vulnerable at their upper parts, and this is why attempts are being made at defining munitions with jet-forming charges whose direction of action is more or less vertical.

Patent FR2771166 describes, for example, a munition which acts by overflying the objective and which has a warhead whose direction of action is more or less normal to the axis of the munition (that is to say more or less the direction of flight of the munition. The munition contains a jet-forming charge whose confinement is of more or less cylindrical shape. The liner is arranged in such a way that the direction in which it is projected is perpendicular to the axis of the cylinder.

One disadvantage of this solution is that the position of the liner with respect to the confinement does not

I

-2allow effective use of all of the explosive present in the confinement. This is the case in particular of the explosive around the periphery of the liner, the detonation of which plays no part in projecting the jet. Furthermore, the jet formed may break up into several pieces.

One object of the invention is to propose a jet-forming charge intended to be used in a munition fired along an axis (direction of action) perpendicular to the axis of the munition and which does not have these disadvantages.

Thus, a particular subject of the invention is a jetforming charge comprising a confinement, a liner intended to form a jet, characterized in that: the confinement more or less forms a tube along an axis, the tube being open, at one end, the tube having a cross section at right angles to the axis falling within a rectangle, the two sides of the rectangle having different lengths, the length of the confinement along the axis and the length of the short side of the rectangle being such that the confinement can be housed within a cylinder of axis parallel to the long side of the rectangle; the liner closes the opening of the confinement in such a way that the jet formed by detonation is set in motion in the direction more or less parallel to the axis of the tube.

One of the main advantages of the invention is that, for a given calibre of munition, it is possible to define a charge the volume of which is not limited by this calibre. The invention makes it possible, by increasing the amount of explosive and the mass of the liner, to obtain a jet that performs better than the jet of an axisymmetric jet-forming charge housed similarly in the munition. In addition, this geometry makes it easier to produce warhead charges the -3characteristics of which observe the planes of symmetry of the charge, particularly for producing warhead charges by casting or compression. The void left between the confinement and the structure of the munition can be used to house electronic modules or for the passage of electrical cables.

According to one embodiment, the length of the short side of the rectangle is more or less equal to the length of the confinement along the axis of the tube.

According to one advantageous embodiment, the cross section of the tube is more or less that of an ellipse.

The makes the confinement easier to machine.

According to one advantageous embodiment, the shape of the liner has two perpendicular planes of symmetry the intersection of which forms the axis of the tube.

According to one advantageous embodiment, the liner has at least one concave face.

According to one advantageous embodiment, the concave face of the liner is spherical or toric or ellipsoidal.

According to one advantageous embodiment, the mean value of the radius of curvature of the concave face of the liner is equal to twice the length of the tube along the axis give or take According to one advantageous embodiment, initiators are placed on the surface of the confinement facing the liner.

According to one advantageous embodiment, initiators are distributed symmetrically with respect to the planes of symmetry of the liner.

-4- According to one advantageous embodiment, there are four initiators.

Other features and advantages of the invention will become apparent from the description which follows, given with reference to the attached drawings: Figures 1 to 3 depict an example of a munition comprising a charge according to the invention in a side view, a view from above, and a radial view, respectively; Figure 4 depicts a horizontal section of the confinement; Figures 5 to 8 depict an example of a charge according to the invention viewed in isometric perspective, in an axial view (along the axis of the munition), viewed from above and viewed from the side, respectively; Figure 9 depicts the liner in an isometric perspective view.

Reference is now made to Figures 1 to 3 which depict an example of a munition comprising a charge according to the invention. The munition 2 has a body essentially cylindrical with respect to an axis of symmetry 3. The axis of symmetry 3 is more or less horizontal, aligned with the direction of travel of the munition when it is in flight. The munition 2 contains a charge 1 placed inside it. This charge has a direction of action 4 that is more or less vertical, that is to say perpendicular to the axis of symmetry 3.

Reference is now made to Figure 4. The charge 1 comprises a confinement 5 in which an explosive warhead charge (not depicted) is placed. The confinement may be made of steel, aluminium or plastic for example. The charge further comprises at least one initiator (not visible in this figure) intended to initiate detonation of the explosive warhead charge. The confinement 5 has an opening closed by a liner 6. The liner is intended to form a jet when the explosive warhead charge is detonated. The liner may be. made of metal, such as tantalum, nickel, iron or copper for example.

Advantageously, when the charge is placed in the munition, the liner is on one side of the munition, within the exterior profile of the munition and flush with the latter in its outermost parts.

The confinement more or less forms a tube along the axis 4. The tube has, in the horizontal plane (the plane perpendicular to the axis 4) a cross section that falls within a rectangle 7. Advantageously, the section of the tube is an ellipse or almost an ellipse. The rectangle 7 has a long side 8 and a short side 9 of different lengths. The long side 8 is parallel to the axis 3. As the confinement is housed in the munition 2, its length along the axis 4 and the length of the short side 9 are limited by the calibre of the munition 2. In other words, the length of the confinement along the axis 4 and the length of the short side of the rectangle are such that the confinement can be housed in a cylindrical tube (portion of munition) the axis of which is parallel to the long side 8.

According to an advantageous embodiment, in order to maximize the useful volume of the charge for a given calibre of the munition, the length of the short side 9 is more or less equal to the length of the confinement along the axis of the tube 4.

Reference is now made to Figures 5 to 8. According to one advantageous embodiment, the liner has two planes of symmetry 10 and 11. These planes of symmetry are perpendicular and their intersection forms the axis of the tube (axis 4).

The initiators 12 may be four in number, and be positioned on the face of the confinement 5 situated facing the liner 6 symmetrically with respect to the -6planes of symmetry 10, 11 of the liner. The liner may itself be symmetric with respect to the planes 10, 11.

Thus, the explosive warhead charge detonates, forming a wave that is symmetric with respect to the planes 11. As the liner is itself symmetric with respect to the planes 10, 11, there is obtained a jet that propagates along the axis 4 and is symmetric with respect to the planes 10, 11.

Reference is now made to Figure 9. According to an advantageous embodiment, the liner has at least one concave face 15. The other face of the liner 16 may be planar or convex (if the liner has a constant thickness for example). The concave face 15 of the liner is advantageously spherical, toric or ellipsoidal.

Advantageously, the mean value of the radius of curvature 14 of the concave face 15 of the liner is equal to twice the length of the tube along its axis 4, give or take Advantageously, the liner contains the entire cross section of the tube. In this example it therefore has a projection in a horizontal plane (plane perpendicular to the axis 4) that has the shape of an ellipse 13.

This makes it possible not only to form a jet more efficiently, but also makes it possible to have an area of contact between the liner and the confinement which is not limited by the thickness of the confinement (contact is with the interior surface of the confinement rather than with an edge of the confinement).

Of course the invention is not restricted to this exemplary embodiment. The number of initiators may differ. The liner may have a variable thickness.

Claims

1. Jet-forming charge comprising a confinement a liner intended to form a jet, characterized in that: the confinement more or less forms a tube along an axis the tube being open at one end, the tube having a cross section at right angles to the axis falling within a rectangle the two sides (8, 9) of the rectangle having different lengths, the length of the confinement along the axis and the length of the short side of the rectangle being such that the confinement can be housed within a cylinder of axis parallel to the long side of the rectangle; the liner closes the opening of the confinement in such a way that the jet formed by detonation is set in motion in the direction more or less parallel to the axis of the tube.

2. Jet-forming charge according to Claim 1, characterized in that the length of the short side (9) of the rectangle is more or less equal to the length of the confinement along the axis of the tube.

3. Jet-forming charge according to either one of the preceding claims, characterized in that the cross section of the tube is more or less that of an ellipse.

4. Jet-forming charge according to any one of the preceding claims, characterized in that the shape of the liner has two perpendicular planes of symmetry 11) the intersection of which forms the axis of the tube.

Jet-forming charge according to any one of the preceding claims, characterized in that the liner (6) has at least one concave face -8-

6. Jet-forming charge according to Claim characterized in that the concave face of the liner is spherical or toric or ellipsoidal.

7. Jet-forming charge according to either one of Claims 5 or 6, characterized in that the mean value of the radius of curvature (14) of the concave face of the liner is equal to twice the length of the tube along the axis give or take

8. Jet-forming charge according to any one of the preceding claims, characterized in that it comprises initiators (12) placed on the surface of the confinement facing the liner.

9. Jet-forming charge according to Claim 4, characterized in that it comprises initiators (12) distributed symmetrically with respect to the planes of symmetry (10, 11) of the liner.

Jet-forming charge according to Claim 9, characterized in that there are four initiators. -9-

11. A jet-forming charge substantially as hereinbefore descrbed with reference to the accompanying drawings.ri Dated 25 November, 2003 TDA Armements SAS Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R:\LIBTT]03496.doc:hxa