Further HDRM defeat device

Abstract

The invention relates to a further HDRM defeat device, there is a high density reactive material (HDRM) munition warhead comprising a main body with a payload cavity capable of receiving a high explosive payload, said cavity comprising, a high explosive, an HDRM material located between the high explosive and the main body, wherein the main body has a concave outer surface, and comprises a plurality of preformed fragments located on the outer surface of the main body, said fragments formed from a further HDRM material, said further HDRM material further comprising tungsten metal in the range of 10 to 50 wt%, such that in use the HDRM material and further HDRM preformed fragments are explosively driven together. such as to allow an explosive output from the high explosive to be more effectively transferred to initiate the HDRM material reaction.

Description

[0001] Further HDRM Defeat Device

[0002] The invention relates to high density reactive materials, preferably materials with a high density and exothermic output for and a liner for the effective takeover of HDRM, particularly for the defeat of soft targets, especially UAS / drones.

[0003] High Density reactive materials (HDRM) are a new emerging class of materials http: / / en.wikipedia.org / wiki / Reactive_materials, which have higher densities than conventional reactive materials such that they may provide enhanced performance with mechanical properties suitable for application in a broad range of weapon systems. This includes potential for effective transfer of Kinetic Energy in impact penetrators, fragments and other systems, whilst offering an additional advantage of providing a further exothermic output under explosive loading or following High Velocity impact.

[0004] According to a first aspect of the invention there is provided a high density reactive material (HDRM) munition warhead comprising a main body with a payload cavity capable of receiving a high explosive payload, said cavity comprising, a high explosive, an HDRM material located between the high explosive and the main body, and wherein the main body comprises a plurality of preformed fragments, such that in use the HDRM material and preformed fragments are explosively driven together; such that the HDRM material reacts on the surface of the preformed fragments.

[0005] In a preferred arrangement the outer surface of the main body may have a curved profile such as for example a concave or convex outer surface, so as to selectively either form a large volume of less densely-populated fragments, or a smaller volume with a higher densely-populated fragments after the detonation of the warhead.

[0006] Preformed fragments may be a plurality of individual discrete elements that are adhered to and bound to the munition main body, or alternatively are capable of forming fragments, by means of an etched / engraved pattern on the munition main body, such that upon detonation the case fragments in a defined pattern. These capable of forming fragments may be slower in velocity as some of the energy is required to form the fragment.

[0007] The use of discrete elements, as preformed fragments, allows for the use of different materials for the munition main body and the preformed fragments. The fragments may be any size or shape, typically less than 30mm, preferably less than 10mm. The use of small sized fragments in this range allows for a multiplicity of fragments to be arranged on the surface of the munition main body, rather than a few large fragments. The fragments may have any surface shape, such as, for example spherical, non-uniform, needle-like, depending on the intended target.

[0008] In a preferred arrangement the preformed fragments may be located on an outer surface of the main body. Whilst the preformed fragments could be located inside the main body, this may reduce the velocity of the fragments.

[0009] The preformed fragments may be selected from any material, preferably a metal, preferably a metal that has a higher density than the metal of the main body of the warhead and / or a material that has a hardness value that is greater than the material of the main body of the warhead.

[0010] The preformed fragments may be selected from an inert, unreactive metal with respect to HDRM compositions, or a further reactive HDRM material, preferably a further HDRM material, yet more preferably a further HDRM material with a high percentage volume of tungsten. The unreactive metal may be selected from any high density metal, such as for example tungsten, alloys of tungsten or metals whose density is greater than steel. The HDRM material located between the high explosive and the main body, may be in the form of a liner on the wall of the payload cavity or a collar which encapsulates the high explosive, such that said high explosive and HDRM collar may be inserted into the payload cavity. The HDRM material is preferably parallel with the high explosive, and preferably parallel to the payload cavity. Preferably the HDRM material, high explosive and payload cavity have parallel walls.

[0011] Where the preformed fragments are selected from inert materials, they have been observed to be coated with the HDRM material as it reacts, thereby causing the fragments to distribute the HDRM further and to impinge on a target, with a reacting HDRM composition.

[0012] In a further arrangement the preformed fragments may have a coating of an HDRM or the further HDRM material located thereon, more preferably the preformed fragments are selected from the further reactive HDRM material. Preferably the further HDRM material (the HDRM fragments) comprises a non reactive high density material such as for example tungsten, whereas the HDRM material that surrounds the high explosive preferably does not contain a further non-reactive material as any non- reactive material reduces the energy output available.

[0013] The HDRM material located around the high explosive is desired to increase the duration of the overpressure of the detonation event. The further HDRM material, such as that on an HDRM fragment is designed to cause thermal damage to the target.

[0014] According to a further aspect of the invention there is provided a high density reactive material (HDRM) munition comprising a tail unit, a main body as defined herein, a fuze, an ogive portion located between said main body and the fuze, and an explosive train operably connected to said fuze and high explosive.

[0015] Preferably the high explosive is a non-ideal or metallised explosive. According to a further aspect of the invention there is provided a method of defeating a target, such as for example an unmanned aerial system(UAS) comprising the step of detonating an HDRM munition as defined herein.

[0016] The HDRM material and optionally further HDRM material may be selected from any known composition, preferably selected from a composition comprising,

[0017] A) at least two separate group 4 metals, present in the range of from 40 to 90%wt

[0018] B) at least one oxidiser or alloying element, present in the range of from 5 to 55%wt wherein said reagents and optional pressing aids are present in substantially 100%wt.

[0019] Preferably wherein B) is at least one oxidiser, carbon or boron.

[0020] The reagent A) group 4 metals are group 4, d-block (transition metals) such as titanium, zirconium, and hafnium. These metals offer high densities, and the specific selection of two different group 4 options offers a chance to target specific density ranges for the final composition whilst retaining similar reactivity.

[0021] For the defeat of small targets, such as for example UAS and especially swarms of targets, it is desirable to subject a large area to a very long time period of intense overpressure and heat. The longer the energetic event occurs, the more chance there is of defeating, immobilising or damaging the targets or at least more of the targets. The use of HDRM substantially increases the bare charge equivalence, ie an increased energetic event is caused, without increasing the amount of high explosive content. The use of the further HDRM preformed fragments, ensures that when the fragment impinges on the target that a further sustained exothermic reaction, ie intense heat is imparted onto the target (in combination with the kinetic energy of the fragment), providing another defeat mechanism. The formulations as defined herein have provided at least a 20% increase in overpressure duration (impulse) and peak overpressure compared to the use of a standard steel encasement. The energetic event has been even further increased when paired with a non-ideal, blast enhancing base explosive, when compared to a standard high explosive. The use non-ideal explosive or aluminised high explosives offer further enhancement of TNT equivalence and their use increased the duration further.

[0022] The increase in the duration of the overpressure allows the blast to do more work on the UAS targets. Blast waves, can, if they have a long time duration may go around corners and act on all surfaces of a target and not just the one it is facing. A slower acting, non-ideal explosive (an explosive that releases some of its energy after the shock front) when paired with HDRM will create afterburn which goes on long after the detonation event, thereby overpressure duration. This means that the explosive event may potentially last between milliseconds and seconds rather than the microseconds, compared to that of a standard explosive which would be 1000 to 1 million time faster, ie much shorter duration.

[0023] The use of a non- ideal explosive with HDRM provided substantially no loss in peak pressure. Typically for explosive events, when you increase impulse you lose peak overpressure but with the formulations according to the invention no loss in peak pressure and a gain in impulse was observed over standard explosives with steel cases.

[0024] Preferably the munition may comprise a proximity fuze. The problem of the prior art fragmenting systems is that the fragmenting system has a narrow window for frag dispersion, meaning that you would have to have exact timings to take out any other drones apart from the one that you had “proximity on”. A large scale, enhanced blast, as caused by the munition according to the invention, will fill a significantly larger volume / region in the air, due to the longer duration of the energetic event, and the increased amounts of overpressure and heat.

[0025] The blast cloud formed using the HDRM is constantly burning so there will be very intense heat as well as burning metallic particles that can get stuck into the UAS materials. An enhanced blast wave, with afterburn would increase the effective blast radius dramatically, compared to a high shock standard blast which decays quickly, so it might get the closest drone and then just knock a few others off course, briefly.

[0026] The proximate to a UAS target may be achieved by the use of a proximity fuze, which detects when the fuze is at a set distance from a target. Alternatively the fuze may be caused to activate after a period of time, upon contact with a UAS target or caused to detonate at a set altitude.

[0027] In a preferred arrangement at least one of the group 4 metals is hafnium. Preferably the hafnium is present in the range of from 20 to 79%wt or more preferably in the range of 20 to 35%wt. The specific inclusion of Hafnium, provides a significant increase to the overall effective density of the consolidated composition, for a relatively minor volumetric inclusion.

[0028] The group 4 metals may offer a range of morphologies - comprising nano, sub micron, or micron sized particulates. The at least two group 4 metals may be selected to maximise mixing capability to promote uniformity of distribution (these may be substantially the same size, or targeted different size ranges to achieve a specific multimodal distribution, such as a bimodal distribution.

[0029] Preferably B) is at least one oxidiser. The at least one oxidiser may preferably present in the range of from 35 to 55%wt.

[0030] The at least one oxidiser may be a metal salt, such as, for example, oxides, nitrates, perchlorates, permanganates, peroxides, chlorates. Preferably a high density metal salt, such as for example, metal oxides, for example CuO.

[0031] The reagent B) when selected from an alloying element may be selected from any non-group 4 metal, metalloid, that undergoes an exothermic alloying reaction with group 4 metals, preferably carbon or boron. The boron may be present in an amount 5 to 20%wt, preferably 10%wt.

[0032] The reagent B may be selected from nano, sub micron, or micron sized particulates, such that upon intimate mixing with group 4 metals, may support / provide a homogenous mixture. The particulate size of the group 4 metals and reagent B materials may be selected to provide multimodal distributions.

[0033] In one arrangement there is a reagent C) a binder in the range of 1 -10%wt. The reagent C) binder may be selected from any polymer binder, or fluoropolymer binder, preferably at least one fluoroelastomer binder. The fluoroelastomer binder may be selected from a range of materials such as for example hexafluoropropylene, vinylidene fluoride, terpolymers of tetrafluoroethylene, vinylidene fluoride and hexafluoropropylene (HFP), perfluoromethylvinylether, THV 220, and PTFE, preferably a Viton, more preferably Viton A.

[0034] The reagent C) binder may preferably be present in the in the range of from 3 to 7%wt, preferably 5%wt.

[0035] The at least two group 4 metals may be encapsulated in a binder.

[0036] In a preferred arrangement, the further HDRM composition comprises a high density non-reactive metal greater than 10%, preferably tungsten metal, in the range of 10 to 50 wt%. The tungsten provides a high density material. The presence of tungsten metal into the composition adds a large amount of mass for a small volume, due to its high density. It is not a reactive substance in the formulation, but the high density provides reactive fragments, with increased mass, and thereby causes more damage to the target, when they are ejected during the energetic event.

[0037] The further HDRM fragments also reduce collateral damage, because they are burning whilst travelling, reducing their mass and size whilst decelerating through drag.

[0038] There is provided a method of defeating a target comprising the step of detonating a high explosive munition comprising a blast enhancement device proximate to the target, wherein the blast enhancement device comprises an HDRM material located on said high explosive, and the further HDRM material in the form of preformed fragments located on the outer surface of the munition case. Preferably the high explosive is a non-ideal explosive or a metallised explosive, such as, for example aluminium metal. Preferably the fuze is a proximity fuze.

[0039] The munition may be any munition that undergoes a detonative or deflagration reaction, such as, for example a shell, mortar, bomb or grenade.

[0040] The munition may comprise a portion of consolidated composition as defined herein. The portion of the munition may comprise all, substantially all or part of a munition. The munition may such as for example be a direct fire or indirect fire munition. The munition may be kinetic energy or chemical energy munition or a combination thereof, such as, for example a projectile, missile, shell, casing, shaped charge liner, preformed fragments, grenade or mortar. The HDRM may be provided as a collar around the high explosive.

[0041] Preferably, the munition may be a gun launched shell, such as for example, 105mm 155mm or any other typically used calibre.

[0042] The particulates of the composition may not be consolidated and may be available as agglomerates / clumps, and may be ignited as such, and undergo ignition and continue to bum in flight. This may offer enhancement to blast and after bum or Kinetic Energy transfer to targets at range.

[0043] The HDRM composition either solid or agglomerates may be ejected, or projected , in such a manner to retain physical form / mass and associated Kinetic Energy allowing reaction on impact with targets at a specific thresh-hold impact velocity causing shock reaction and ignition of the material on the surface or within the target structure.

[0044] There is provided a high density reactive material composition comprising, at least two group 4 metals, present in the range of from 45 to 90%wt tungsten in the range of from 40 to 70%. wherein said reagents and optional pressing aids are present in substantially 100%wt. Preferably wherein said consolidated composition provides an effective density by weight fraction of greater than 10.

[0045] Table 1

[0046] Table 1 provides a number of examples where the composition comprises a group 4 metal present in the range of from 45 to 95%wt. the materials are sintered, preferably using both elevated temperatures and pressure with the a binder and optional pressing aids to facilitate consolidation.

[0047] Table 2

[0048] Table 2 above, provides preferred examples of compositions, wherein there is further provided tungsten metal and at least two different group 4 metals are selected.

[0049] The group 4 metals may be encapsulated or a passivation layer, or sacrificial layer to prevent reaction with air, moisture or unwanted reactions with the other reagents, until activated in the designed mode of use. The group 4 metals may be encapsulated with at least one inert material, to prevent reaction with moisture or air. Preferably by premixing the group 4 metal with reagent C) a binder, preferably a fluoroelastomer. The coating / microencapsulation of the group 4 metal may prevent combustion in air during the sintering process.

[0050] According to a further aspect of the invention there is provided a target defeat system comprising a platform, at least one gun barrel and at least one munition defined herein, and operated according to a method defined hereinbefore. The platform may be a vehicle, vessel, craft or land based. The platform may have a combat system, radar and other means for detecting, and setting the fuze on the munition, and firing the munition to engage with at least one target.

[0051] In a highly preferred arrangement there is provided a high density reactive material (HDRM) munition warhead comprising a main body with a payload cavity capable of receiving a high explosive payload, said cavity comprising, a high explosive, an HDRM material located between the high explosive and the main body, wherein the main body has a concave outer surface, and comprises a plurality of preformed fragments, located on the outer surface of the main body, said fragments formed from a further HDRM material, said further HDRM material comprising tungsten metal, in the range of 10 to 50 wt%, such that in use the HDRM material and further HDRM preformed fragments are explosively driven together.

[0052] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic Figures in which:

[0053] Figure 1 schematically depicts a vessel firing at a plurality UAS devices;

[0054] Figure 2 schematically depicts a shell comprising an HDRM case;

[0055] Figure 3 shows the assembly of Figure 2 with an HDRM liner, inside the main body of a shell;

[0056] Fig 4 shows a further HDRM pre-formed fragment warhead with HDRM collar.

[0057] As seen in Figure 1 there is a UAS defeat system 1 , a battleship 2 is located on a body of water 4, and comprises a gun 6 having a gun barrel 7. Other examples may not include a particular vehicle, and could simply comprise a gun, e.g. on static land or water-based platform. In order to engage and defeat a UAS system 9 a munition 5 is launched into the air from the gun barrel 7. The munition is a shell and comprises an HDRM liner. This allows the battleship 2 to deploy the shell 5 at significant range, and accuracy. The shell when proximate to the UAS 9 will be cause to detonate, and the HDRM material will cause a large overpressure in the vicinity of the UAS and for an increase duration, which will be able to defeat a plurality UAS 9 systems. It will be recognised by the person skilled in the art that other platforms or vessels aside from the example battleship 2 could be employed by the present invention, including but not limited to: land- based vehicles; land platforms; or aircraft. Figure 2 shows a high explosive shell 22, with a unitary main body 15 formed from an HDRM material, with a driving band 14 located thereupon. A tail unit 12 is located at the aft of the main body 15. The tail unit 12 is made from aluminium and contains a male threaded portion, which engages with a reciprocal female threaded portion located at the aft of the main body 15. The tail unit 12 may be a boat tail or base bleed unit.

[0058] The payload 23 which may be a high explosive, or aluminised high explosive 20 is located in the payload cavity 24. The payload is a removable liner 21 which is pre-filled with the high explosive 20. The removable liner 21 and high explosive 20 are loaded into the payload cavity 24 in a single step.

[0059] The ogive element receives the explosive train 18 and fuze 19. Upon operation of the fuze 19, the explosive train 18 provides a greater detonative event sufficient to detonate the high explosive 20. The fuze may be a proximity fuze, timed fuze, or point detonating fuze.

[0060] Figure 3 shows an empty shell 25 made from steel, with a fuze 29, located at the forward end. The removable liner 31 is an HDRM material, which contains the high explosive fill (not shown) which can be inserted from the rear of the shell 25. The tail unit 32 may then be secured to the shell 25 to provide the complete shell. The tail unit 32 may be secured to the main body 25 by a cooperative thread, shearable cooperative thread, or shear pins.

[0061] Turning to fig 4 there is shown a warhead 60, which may be a payload of a shell, or the warhead of a guided munition. The warhead 60 is formed from a munition casing 61 , which defines a payload cavity 64. The payload cavity 64 comprises a high explosive 63 and located on the outer surface of the explosive there is a collar or coating of HDRM material 62. The HDRM 62, is located between the casing 61 and the high explosive 63. On the outer surface 65 of the munition casing 64 is located a plurality of un-reactive ie inert preformed fragments 66. The munition casing 61 may have a curved surface 67 a concaved surface, to allow a greater angle of dispersement of the preformed fragments 66. It is desirable for the HDRM reaction to start at or near the peak of the detonative peak pressure.

Claims

CLAIMS1. A high density reactive material (HDRM) munition warhead comprising a main body with a payload cavity capable of receiving a high explosive payload, said cavity comprising, a high explosive, an HDRM material located between the high explosive and the main body, and wherein the main body comprises a plurality of preformed fragments, such that in use the HDRM material and preformed fragments are explosively driven together.

2. A munition according to claim 1 , wherein the main body has a concave or convex outer surface.

3. A munition according to claim 1 or claim 2 wherein the preformed fragments are located on the outer surface of the main body.

4. A munition according to any one of the preceding claims wherein the preformed fragments are selected from a material with a higher density than the main body of the warhead.

5. A munition according to any one of the preceding claims wherein the preformed fragments have a coating of or are formed from a further HDRM material.

6. A munition according to any one of the preceding claims wherein high explosive is a non-ideal or metallised explosive.

7. A munition according to any one of the preceding claims, wherein the HDRM material, high explosive and payload cavity have parallel walls.

8. A munition according to any one of the preceding claims wherein the HDRM and / or further HDRM is selected from a composition comprising,A) at least two separate group 4 metals, present in the range of from 40 to 90%wtB) at least one oxidiser or alloying element, present in the range of from5 to 55%wtwherein said reagents and optional pressing aids are present in substantially 100%wt.

9. A munition according to claim 8, wherein B) is at least one oxidiser, carbon or boron.

10. A munition according to claim 8 or 9, wherein the at least one oxidiser is a metal oxide.

11. A munition according to any one claims 8 to 10, wherein at least one of the group 4 metals is hafnium.

12. A munition according to claim 11 , wherein the hafnium is present in the range of from 20 to 79%wt.

13. A munition according to any one claims 8 to 12, wherein there is a reagent C) a binder in the range of 1-10%wt.

14. A munition according to any one of the preceding claims wherein the HDRM is selected from a composition comprising tungsten metal, in the range of 10 to 50%wt.

15. A high density reactive material (HDRM) munition warhead comprising a main body with a payload cavity capable of receiving a high explosive payload, said cavity comprising, a high explosive, an HDRM material located between the high explosive and the main body, wherein the main body has a concave outer surface, and comprises a plurality of preformed fragments located on the outer surface of the main body, said fragments formed from a further HDRM material, said further HDRM material further comprising tungsten metal in the range of 10 to 50 wt%, such that in use the HDRM material and further HDRM preformed fragments are explosively driven together.

16. A method of defeating an unmanned aerial system(UAS) comprising the step of detonating a high explosive munition comprising an HDRM munition, as claimed in any one of the preceding claims, proximate to at least one UAS.

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