Warhead casing

Warheads used for various weapons systems typically comprise warhead casings manufactured from aluminium or steel. These materials are chosen for the casings since they need to be strong and have sufficiently low weight. However, such warheads have the disadvantage that they are likely to cause collateral damage, due to splinter from the warhead casing.

Attempts have been made to find alternative materials for warhead casings. In U.S. Pat. No. 5,000,093 A, a warhead casing is described which is made by isostatically pressing a mixture of magnesium and aluminium powder into a preform and then sintering the preform. This method may be suitable for simple warhead configurations, whereas more complicated configurations require additional machining after sintering. DE 10208228 describes a rotation symmetrical grenade having a casing of porous aluminium.

There is a desire to avoid collateral damage, and thus there is a need to provide a warhead casing that fulfils the requirements set on warhead casings regarding weight and strength, but which does not cause collateral damage.

According to the present invention a warhead casing is provided which is made up of laser sintered material. A laser sintered warhead casing presents several advantages over the casings previously available. It is splinter proof, whereby collateral damage can be avoided, and it can be made in one piece as opposed to steel or aluminium metal casings which have to be manufactured in separate components which are finally assembled. Moreover, laser sintering of the warhead casing allows for more complex geometries than have previously been possible to obtain for warheads in a simple way.

The laser sintered material has a density that is sufficiently low, for use in a warhead casing, and the weight is lower than the weight of aluminium alloys, which have a density of 2.7-2.8 g/cm³.

By manufacturing casings for warheads or warhead modules by selective laser sintering technique, a decrease in the weight of such components can be achieved, since laser sintered materials have lower density than solid materials.

Warhead casings are typically rotationally symmetrical. However, due to the flexibility of laser sintering other geometries may be contemplated, so that the warhead casing may be unsymmetrical. The warhead casing has the form of a hollow container, which is typically provided with an opening for filling of explosive. The hollow container comprises one or more wall surface portions, which constitute the container wall. The wall surface portions may be flat or curved. The filling opening may be a cylindrical portion protruding from one of the wall surfaces.

As an example, the warhead casing may have an unsymmetrical geometry, defining a hollow body, having a flat upper wall and a somewhat curved lower wall opposite the upper wall, a rear flat wall and a front flat wall. The height of the hollow body is larger at the rear end, than at the front end. An opening for filling with explosives is arranged in the flat upper surface, close to the rear wall.

FIGS. 1-3 illustrate examples of different geometries for warhead casings. The warhead casing of FIG. 1 has an opening 1 for filling of explosive 2, arranged in a flat upper wall 3, from which three flat wall surfaces 4a, 4b, 4c extend sloping slightly downwards. All these three flat wall surfaces are connected to a rounded wall surface 5 which constitutes the wall opposite the filling opening. In one of the flat surfaces 4b and partly in the rounded wall surface is provided an indentation 6.

FIG. 2 illustrates a geometry in which the filling opening 7 extends from a circular surface 8, from which a rounded surface 9 extends downwardly in the form of a truncated cone. At the lower end of the lower wide end of the conical surface flat surfaces 10 extend. Three indentations 11 are provided in these flat surfaces. The bottom surface 12 opposite to the filling opening is flat.

The geometry illustrated in FIG. 3 has the form of an elongated container having the filling opening (not shown) arranged in a side wall at the end of a truncated cone. The longitudinal cross-sectional area at the centre of the container (the cross-section of which is shown in FIG. 3) is larger than the cross-sectional area at each side of the container. Indentations 13 are provided in the central portion of the container wall surface.

Laser sintering has hitherto primarily been used for manufacturing of prototypes for this application. The strength of laser sintered material is not sufficient without reinforcement for extremely high launch forces, but good enough for moderate launch forces. Laser sintering allows for shaping of complex geometries in one piece, and normally no further machining is required, except possibly clearing of screw threads. An example of the laser sintering technology is described in EP0734842A1.