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United States Patent Application	20100282062
Kind Code	A1
Sane; Ajit Y. ;   et al.	November 11, 2010

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Claims

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1. A hybrid armor architecture adapted to protect a body panel from a high-energy ballistic threat, said architecture comprising a laminate reactive armor panel, an armor plate disposed behind said laminate reactive armor panel and a flyer plate disposed behind said armor plate,said laminate reactive armor panel comprising a layer of non-explosively reactive material sandwiched between outer layers of ductile material,said flyer plate or a portion thereof being configured to move toward and impact said body panel on impact of a high-energy ballistic projectile with said flyer plate or said portion thereof, to thereby increase the total area of impact with said body panel relative to the projectile alone.

2. The armor architecture of claim 1, comprising a plurality of said laminate reactive armor panels spaced apart from one another by a distance of 1/8 inch to 2 inch.

3. The armor architecture of claim 2, said layers of ductile material in each of said laminate reactive armor panels being aluminum layers having a thickness of 0.05 to 0.25 inch.

4. The armor architecture of claim 3, said layer of non-explosively reactive material in each of said laminate reactive armor panels being a polyethylene layer having a thickness of 0.1 to 0.5 inch.

5. The armor architecture of claim 1, said armor plate comprising steel rolled homogeneous armor having a thickness of 0.1 to 0.75 inch.

6. The armor architecture of claim 1, said flyer plate comprising a plurality of discrete plate sections that are attached to one another in a coplanar arrangement to form said flyer plate.

7. The armor architecture of claim 6, said flyer plate being formed from a single sheet of material, said plurality of discrete plate sections being formed therein by a series of slits provided through the flyer plate to provide an array said discrete plate sections that remain attached to one another.

8. The armor architecture of claim 7, said discrete plate sections being substantially square in shape and remaining attached to adjacent ones at their respective corners.

9. The armor architecture of claim 8, said substantially square-shaped plate sections having dimensions of about 4-inches by 4 inches.

10. The armor architecture of claim 6, said flyer plate having a thickness of 0.1 to 0.75 inches.

11. The armor architecture of claim 2, said plurality of laminate reactive armor panels being disposed in a first armor module, said armor plate and said flyer plate both being disposed in a second armor module, the first armor module being removably secured to the second armor module to provide all of said laminate reactive armor panels, armor plate and flyer plate in layered arrangement at selected distances from one another.

12. The armor architecture of claim 11, further comprising a reinforcing layer disposed in said second armor module between said armor plate and said flyer plate.

13. The armor architecture of claim 11, further comprising a further reinforcing layer disposed behind said flyer plate in said second armor module.

14. The armor architecture of claim 1, said outer layers of ductile material being inner and outer concentric tubes and said layer of non-explosively reactive material being disposed in the space defined between said inner and outer concentric tubes, said laminate reactive armor panel comprising a plurality of pairs of said inner and outer concentric tubes arranged in a layer array.

15. The armor architecture of claim 14, said layer array of pairs of inner and outer concentric tubes being sandwiched in between additional layers of material to provide said laminate reactive armor panel.

16. The armor architecture of claim 2, said plurality of laminate reactive armor panels being parallel to one another.

17. The armor architecture of claim 2, said plurality of laminate reactive armor panels being alternately arranged at oblique angles.

18. The armor architecture of claim 1, comprising a plurality of said flyer plates.

19. The armor architecture of claim 1, comprising a plurality of said armor panels.

20. The armor architecture of claim 1:said ductile material of the outer layers of said laminate reactive armor panel being selected from the group consisting of copper, aluminum, iron, steel, molybdenum, tantalum, magnesium, titanium and alloys of these, and non-metallic materials that possess ductility, including fiberglass, fiber-reinforced polymers and elastomers polymers;said non-explosively reactive material being selected from the group consisting of polyethylenes, gum rubbers, polytetrafluorethylenes, polyurethanes and copolymers thereof, mixtures of zinc and sulfur or sulfur embedded within incompressible liquids or waxes, aluminum powder mixed with perchlorates, inorganic ammonium salts, and low-molecular-weight materials prone to sublimation, mixtures of thermite and easy-to-sublime materials, materials participating in ballotechnic reactions and mixtures of the foregoing;said armor plate and flyer plate each individually being made of a material selected from the group consisting RHA, HHA, dual hard steel armor, alloy steels, titanium alloys, reinforced metals, reinforced plastics, ceramic layers backed by RHA or other composite materials, and combinations thereof, either alone or in conjunction with reinforcing materials.

21. The armor architecture of claim 20, said ductile material layers being 0.125 inch thick, said non-explosively reactive material layers being 0.25 inch thick, said armor plate being 0.375 inch thick and said flyer plate being 0.375 inch thick.

22. The armor architecture of claim 1, said armor plate being made from a material selected from the group consisting of RHA, HHA, dual hard steel armor, alloy steels, titanium alloys, reinforced metals, metal backed by a ceramic material, metallic fiber reinforced polymer, non-metallic fiber reinforced polymer, reinforced ceramic, monolithic ceramic, lithium aluminosilicate glass ceramic, strengthened glass, silicon, boron carbides, silicon carbides, titanium, aluminum nitrides, aluminum oxides or carbon-based composites.

23. The armor architecture of claim 1, said flyer plate being made from a material selected from the group consisting of RHA, HHA, dual hard steel armor, alloy steels, titanium alloys, reinforced metals, metal backed by a ceramic material, metallic fiber reinforced polymer, non-metallic fiber reinforced polymer, reinforced ceramic, monolithic ceramic, lithium aluminosilicate glass ceramic, strengthened glass, silicon, boron carbides, silicon carbides, titanium, aluminum nitrides, aluminum oxides or carbon-based composites.

24. The armor architecture of claim 1, said flyer plate having an elongation to failure greater than 5% and a tensile strength greater than 40,000 psi.

25. The armor architecture of claim 1, said flyer plate having at least one characteristic selected from an (i) an elongation to failure greater than 5% or (ii) a tensile strength greater than 40,000 psi.

26. A hybrid armor architecture adapted to protect a body panel from a high-energy ballistic threat, said architecture comprising:a plurality of laminate reactive armor panels, each said panel comprising a layer of non-explosively reactive material sandwiched between outer layers of ductile material, said laminate reactive armor panels being spaced from one another a distance of 0.125 to 0.5 inch;an armor plate having a thickness of 0.1 to 0.75 inch disposed 0.5 to 1 inch behind the laminate reactive armor panel that is to be positioned nearest the body panel in use;and a flyer plate having a thickness of 0.1 to 0.75 inches disposed 4 to 8 inches behind the armor plate, said flyer plate or a portion thereof being configured to move toward and impact said body panel on impact of a high-energy ballistic projectile with said flyer plate or said portion thereof, to thereby increase the total area of impact with said body panel relative to the projectile alone.

27. The armor architecture of claim 26, said layers of ductile material and said layer of non-explosively reactive material being aluminum and polyethylene layers, respectively, said armor plate and said flyer plate both comprising rolled homogeneous armor.

28. The armor architecture of claim 27, said flyer plate being formed from a single sheet of material having a series of slits provided through the flyer plate to provide an array of discrete plate sections that remain attached to one another.

29. The armor architecture of claim 28, said discrete plate sections being substantially square in shape and remaining attached to adjacent ones at their respective corners.

30. The armor architecture of claim 27, said plurality of laminate reactive armor panels being disposed in a first armor module, said armor plate and said flyer plate both being disposed in a second armor module, the first armor module being removably secured to the second armor module to provide all of said laminate reactive armor panels, armor plate and flyer plate in layered arrangement at the specified distances from one another.

31. The armor architecture of claim 27, said aluminum layers being 0.125 inch thick, said polyethylene layers being 0.25 inch thick, said armor plate being 0.375 inch thick and said flyer plate being 0.375 inch thick, said laminate reactive armor panels being parallel and spaced 0.25 inch from one another, said armor panel being spaced 0.5 to 1 inch behind the laminate reactive armor panel that is to be positioned nearest the body panel in use, said flyer plate being spaced about 6 inches behind said armor plate, said flyer plate further being adapted to be spaced about 2 inches from said body panel in use.

32. A hybrid armor architecture adapted to protect a body panel from a high-energy ballistic threat, said architecture comprising a laminate reactive armor panel and at least one component selected from the group consisting of (i) an armor plate disposed behind said laminate reactive armor panel or (ii) a flyer plate disposed behind said laminate reactive armor panel, wherein said laminate reactive armor panel comprises a layer of non-explosively reactive material sandwiched between outer layers of ductile material.

33. The armor architecture of claim 32, said flyer plate or a portion thereof being configured to move toward and impact said body panel on impact of a high-energy ballistic projectile with said flyer plate or said portion thereof, to thereby increase the total area of impact with said body panel relative to the projectile alone.

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Description

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[0001]This application claims the benefit of U.S. provisional applications Ser. Nos. 60/988,468 filed Nov. 16, 2007 and 61/004,853 filed Nov. 30, 2007, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002]Improvised explosive devices (IEDs) present a significant challenge to conventional armor architectures. One type of IED that has been particularly difficult to defeat is that which produces explosively-formed projectiles (or EFPs). One such EFP device is schematically illustrated in FIG. 1, wherein a high explosive (such as plastic explosive or C4) is placed in a tube or a can having an open end. A bowl-shaped sheet of metal, typically copper, is placed at the open end with its concave surface facing outward, so that the high explosive is enclosed within the tube or can behind the copper sheet. This improvised device is positioned so that the concave surface of the copper sheet faces the target or the location where the target is expected. When the explosive is detonated, the force of the explosion drives the metal (copper) plate toward the target at high speed. At the same time, thermal energy causes the copper plate to become semi-molten or molten. As it travels in the molten or semi-molten state, aerodynamic forces acting on the copper material cause it to change shape and form into a generally elongate rod-like shape as illustrated in FIG. 2.

[0003]FIG. 2 illustrates the copper plate at T.sub.0 in its state and shape prior to detonation. At times T.sub.1, T.sub.2 and T.sub.3 following detonation, the plate (now an explosively-formed projectile or EFP) is continuously reshaped through the action of aerodynamic forces as it flies through the air toward its target. As will be appreciated, the projectile is effective to concentrate a large amount of energy in a very small area due to the manner in which it is plastically reformed as it flies in the semi-molten or softened state. The degree of penetrative ability of the EFP will, of course, be depend on a number of factors including, the material and ductility of the metal plate (copper is common due to its ductility), the force of the detonation, the dimensions of the device and the distance between it and the target. Four to ten feet is considered a typical range for EFPs to be effective to penetrate most conventional armor plating materials, such as the conventional rolled-homogeneous steel armor or RHA.

[0004]The EFPs themselves, once formed, typically travel at velocities in the range of 2-4 km/sec. A typical EFP weighing about 500 grams (1 pound) can deliver about 2-3 megajoules (MJ) of energy on impact traveling at about 2.5-3.5 km/sec, concentrated in an area of not more than several square inches. Consequently, such EFPs easily penetrate expedient armor installed on vehicles made from conventional armor materials, including RHA. Therefore, to defeat such threats using conventional materials, the thickness of the armor layers or plates is increased, making the vehicles excessively bulky, heavy and prone to mechanical failures. For example, if an EFP would penetrate 4'' to 5'' thick conventional RHA, then an RHA or steel plate of sufficient thickness to defeat the threat would have a corresponding areal density in the range of 160-200 pounds per square foot. Therefore, a vehicle that needs a protective area of 100 square feet would require steel/RHA armor in excess of 16,000-20,000 lbs., making it practically an impossible solution.

[0005]Accordingly, there is a need in the art for an armor architecture that is effective against EFPs and other substantial penetrative threats that concentrate a large amount of force over a small impact area. Such an improved architecture preferably will be effective to both disperse the concentrated impact energy as well as deflect the projectile itself from its initial trajectory. Most preferably, the improved architecture will be effective to continually realign the projectile trajectory, further dissipating its penetrative power.

SUMMARY OF THE INVENTION

[0006]A hybrid armor architecture adapted to protect a body panel from a high-energy ballistic threat is disclosed. The architecture includes a laminate reactive armor panel, an armor plate disposed behind the laminate reactive armor panel and a flyer plate disposed behind the armor plate. The laminate reactive armor panel has a layer of non-explosively reactive material sandwiched between outer layers of ductile material. The displacement of such a ductile plate or a portion thereof is configured to move toward and impact projectile causing a disturbance in its trajectory. This is usually followed by an armor plate or armor body that bears a significant part of the projectile impact and further destabilize it. Finally a break-away plate or flyer plate or plates are provided close to the body panel so that on impact of a high-energy ballistic destabilized projectile with the flyer plate or the portion thereof, to thereby increase the total area of impact with the body panel relative to the projectile alone.

[0007]As will be seen, the disclosed architecture typically includes a three-part system including the laminate reactive panel, armor plate disposed behind the reactive panel and a displacement or `flyer` plate as hereafter described. Since threat severity can vary widely, it is to be understood that each of these parts may include multiple of the described panels or plates; for example, multiple laminate reactive panels, armor plates and/or flyer plates may be incorporated to provide the armor architecture in various embodiments. In exemplary embodiments, the flyer plate has break-away parts that break of from the main body upon impact and redistribute impact force over much greater area of contact. This plate is termed a `flyer plate` herein with the understanding that it flies towards the vehicle to expand the area of impact with the vehicle body, as will become apparent in the following description.

[0008]A hybrid armor architecture adapted to protect a body panel from a high-energy ballistic threat is further disclosed. The architecture includes a plurality of laminate reactive armor panels, each panel having a layer of non-explosively reactive material sandwiched between outer layers of ductile material, wherein the laminate reactive armor panels are spaced from one another a distance of 0.125 to 0.5 inch. An armor plate having a thickness of 0.1 to 0.75 inch disposed 0.5 to 1 inch is disposed behind the laminate reactive armor panel that is to be positioned nearest the body panel in use. A flyer plate having a thickness of 0.1 to 0.75 inches is disposed 4 to 8 inches behind the armor plate. The flyer plate or a portion thereof is configured to move toward and impact the body panel on impact of a high-energy ballistic projectile with the flyer plate or the portion thereof, to thereby increase the total area of impact with the body panel relative to the projectile alone.

[0009]The number of each type of panel/plate in each part of the architecture, their dimensions and material composition are dependent upon the severity of the threat. For highly energetic threats, it may be necessary or desirable to deploy additional numbers of panels/plates in each part of the architecture or in only some part of the architecture. Alternatively, depending on the threat level, the hybrid armor architecture can comprise a laminate reactive armor panel and at least one component selected from either an armor plate disposed behind the laminate reactive armor panel or a flyer plate disposed behind the laminate reactive armor panel. Nonetheless the embodiments described herein can provide significant weight savings relative to an comparable amount of RHA or other similar steel armor solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]Aspects of the invention will be appreciated by the person having ordinary skill in the art based on the following description with reference to the following drawings, which are provided by way of illustration and not limitation. The drawings are schematic or cartoon in nature, and are not drawn to scale. No dimensions are implied or should be inferred from the appended drawings, in which:

[0011]FIG. 1 is a schematic illustration of an EFP device as explained above.

[0012]FIG. 2 illustrates, schematically, the formation and progression of an EFP from an original bowl-shaped metal (or copper) plate starting from T.sub.o (before detonation) and continuing as it propagates through the air.

[0013]FIG. 3 is a schematic side view of a hybrid armor architecture according to an embodiment of the invention.

[0014]FIG. 4 shows a plan view of a flyer plate according to an embodiment of the invention. However there are many ways and many patterns in which such a concept can be practiced. Numerous other configurations are described below, but not necessarily illustrated for the sake of brevity.

[0015]FIG. 5 is a cartoon illustration of the behavior of a laminate non-explosive reactive armor panel 12 in impact of an EFP 4, according to an illustrated embodiment. As mentioned above, this cartoon is not to scale and the relative dimensions of the EFP and armor components may be different from what is depicted in FIG. 5. The main point is the laminate armor panel 12 interacts with EFP to destabilize or break the EFP apart.

[0016]FIG. 6 illustrates alternative embodiments wherein the laminate panels 12 are arranged at oblique angles relative to the trajectory of an EFP, either parallel (6a) or alternating (6b) relative to one another.

[0017]FIG. 7 illustrates a further alternative embodiment of the hybrid armor architecture shown in FIG. 3, wherein a reinforcing layer 17 is disposed behind an armor plate 14.

[0018]FIG. 8 illustrates a further alternative embodiment wherein the laminate non-explosive reactive armor panels 12 include a series of concentric, circular metal tubes 22a, 22b having an non-explosively reactive material 23 disposed in the annular space defined between concentric circular tubes.

[0019]FIG. 9 illustrates a further alternative embodiment similar to FIG. 8, except where the concentric tubes are square or rectangular instead of circular.

[0020]FIG. 10 illustrates an embodiment of the armor architecture disclosed herein, in modular form and including exemplary attachment structure to attach and retain the modules to a body panel 5 to be protected.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021]Herein, when a range such as 5-25 (or 5 to 25) is given, this means preferably at least 5 and, separately and independently, preferably not more than 25.

[0022]The armor architectures disclosed herein are designed to defeat projectiles, such as an EFP, an RPG (rocket propelled grenade) or a 0.50 Cal M2 round, through a combination of cumulative effects that both destabilize and deflect an incoming projectile, as well as disperse and consume substantial proportions of the projectile's energy. The armor architectures described herein achieve these effects prior to the projectile impacting the skin of a vehicle or other similar structure that the armor is employed to protect. Because much of the projectile's penetrative force is dissipated or consumed by the armor architecture prior to impacting the vehicle (or other contrivance) body, it is rendered incapable to penetrate that body before impacting it.

[0023]An exemplary embodiment of improved armor includes a hybrid architecture that combines non-explosive reactive and passive armor components as will be further described. Such an embodiment is illustrated schematically in FIG. 3. In the figure, the armor architecture is illustrated based on a projectile 4, such as an EFP, approaching along a trajectory from the left side of the figure, with a vehicle body panel 5 or other similar panel to be protected located right-most. The armor architecture 10 illustrated in FIG. 3 includes a series of laminate non-explosive reactive armor panels 12 facing the EFP. An armor plate 14, such as a passive armor plate, is disposed behind the laminate panels 12. An additional plate, referred to herein as a flyer plate 16, is disposed behind the armor plate 14. In the illustrated embodiment, the flyer plate 16 is disposed nearest to the vehicle body panel 5. Each of the aforementioned components will now be further described. Each of the above components will now be described, followed by a description of how they function in complementary fashion to defeat an EFP or other high-energy ballistic threat.

[0024]The laminate reactive-armor panels 12 are described first. The term non-explosive reactive means that the laminate does not contain any explosive or detonating material but it does contain material that can gasify and create pressure on the two adjoining plates and push them apart. As a result these laminates do not pose any safety issues by unintentional setting off of explosives as in the case of explosive reactive armor. Each laminate panel 12 includes at least two outer layers 12a of a ductile material (elongation to failure preferably >5%) and an inner layer 12b made of a non-explosively reactive material sandwiched between the two outer layers 12a. By non-explosively reactive, it is meant that as an EFP contacts and travels through layer 12b, the material of layer 12b is caused to significantly volumetrically expand as the result of either a) expansive vaporization through absorption of thermal energy provided by an EFP and consequent phase-change to a gaseous state, or b) a non-explosive chemical reaction that produces expansive gaseous products. Such volumetric expansion of the material includes a class of reactions called ballotechnic reactions which are essentially pressure induced but non-detonating. If expansion is achieved through a chemical reaction, it is preferred the reaction is exothermic so as to maximize the heat developed and consequent expansion of the resulting gaseous product. The term `non-explosive` in this context means that the material in layer 12b is not an incendiary, pyrophoric or detonating material--it does not mean that the material does not `explode` in the sense that it `expands in volume` or ruptures the outer layers 12a sandwiching it in between. For example, zinc and sulfur can react exothermically to produce zinc sulfide. The resultant temperature rise is sufficient to cause sublimation of zinc sulfide thus giving rise to a high volume of expansive gas. Alternately a mixture of sulfur and petrolatum in the form of paste can be used to produce highly volatile products upon impact. However, this is an endothermic reaction. Therefore selection is not restricted to exothermic reactions. As will be explained shortly, a primary function of the layer 12b is to rupture and expand the outer layers 12a. The material of layer 12b should be stable in general, but effective to react and expand substantially on input of substantial thermal energy as generated by an impacting EFP as described above. A simple calculation can show that rapid conversion of a material like polyethylene into gaseous monomers (extreme impact conditions are expected to unzip the polymer) can generate pressures in excess of 900-1000 atmospheres. For example, a mass of polyethylene having a diameter of 5 cm, which is comparable to the size of holes observed in a typical EFP (described in an example later), and a thickness of about 6 mm could generate a pressure in excess of 970 atmospheres or 13780 psi upon instantaneous gasification from a high energy impact. Such a force would be sufficient to force open the plates 12a and make them move away from each other. These high values are based on the assumption that the temperature of gas remains under standard condition, which is unlikely. So if it is accepted that a temperature rise would occur, then the pressure values given above would increase. Since the temperature of gas is not known, the pressure values given above serve as the least amount of pressure that could be expected from such a gasification event, such as an EFP passing through the material of layer 12b.

[0025]The ductile material used for layers 12a can be made from metals such as copper, aluminum, iron, steel, molybdenum, tantalum, magnesium, titanium and/or alloys of these. Alternatively, the layers 12a can be made from non-metallic materials that possess ductility, including fiberglass, fiber-reinforced polymers and elastomers polymers including filled elastomers. Of these, metallic materials are preferred for reasons that will be explained. The non-explosively reactive material for layer 12b can be selected from among a range of materials that either will chemically react to produce expansive gaseous products or themselves be vaporized and caused to expand from thermal energy delivered by the EFP. If the latter, the material for layer 12b should be selected to have a low enthalpy of vaporization (.DELTA.H.sub.v) so that it will be more rapidly vaporized and then caused to expand on application of thermal energy from the EFP. Examples of suitable materials for layer 12b include polymers such as polyethylene polymers, gum rubbers, Teflon.TM. polymers (polytetrafluorethylenes), polyurethanes and copolymers thereof. They also include materials participating in ballotechnic reactions in which intense pressure is required (experienced in EFP events) to initiate chemical reactions. Examples of reactive materials for layer 12b, which produce expansive gaseous products through non-incendiary reactions, include mixtures of zinc and sulfur embedded within incompressible liquids or waxes, propoellants such as aluminum powder mixed with perchlorates, inorganic ammonium salts such as NH.sub.4NO.sub.3, (NH.sub.4).sub.2S, etc., and low-molecular-weight materials prone to sublimation such as elemental sulfur or cakes thereof. In addition, it is possible to combine highly exothermic reactions such as thermite (a mixture of aluminum powder and iron oxide) and easy-to-sublime materials like zinc sulfide, sulfur, low molecular weight polyethylnes, gum rubber, Teflon or PTFE etc.

[0026]In a preferred embodiment, the outer layers 12a of the laminate panels 12 are aluminum layers and the material of layer 12b is a polyethylene sheet. Preferably, the outer layers 12a of each panel 12 have the same thickness, preferably 0.05-0.25, preferably 0.08-0.2, preferably 0.1-0.15, preferably 0.125, inch. Layer 12b preferably has a thickness of 0.1-0.5, preferably 0.15-0.4, preferably 0.2-0.3, preferably 0.25, inch. An armor plate 14 is disposed behind the laminate non-explosive reactive armor panels 12 relative to the trajectory of an EFP 4. The armor plate 14 can be a layer of conventional armor material, such as steel RHA. Alternatively, it can be a metal plate such as iron, steel, stainless steel, titanium, or an alloy of these with or without other metals to impart greater strength (for example with molybdenum, tantalum, nickel, copper, etc.), as well as metallic or non-metallic fiber reinforced polymer, metal or ceramic composites, reinforced or monolithic ceramics such as lithium aluminosilicate glass ceramics, strengthened glasses, boron carbides, carbides of silicon, titanium, nitrides of aluminum, silicon, titanium, oxides of aluminum, silicon and mixtures thereof or carbon-based composites. The armor plate 14 is a plate of strong material, which can include metals as described above, which are used in conventional armor plating, alone or in conjunction with other reinforcing materials such as in a laminate with Kevlar, fiberglass mats, fiber-reinforced polymer mats, etc. One alternative material is composed of a ceramic layer that is backed by RHA or other composite materials or combination of armor materials termed as hybrid armor materials in which layers of armor materials are combined to form a highly effective armor plate. The armor plate 14, which in another preferred embodiment is composed of steel RHA, preferably has a thickness of 0.1 to 2, preferably 0.2 to 0.5, preferably 0.3 to 0.4, preferably 0.375, inches. Alternatively, a plurality of armor plates 14 may be provided, each individually having a thickness within the specified ranges, or all of which together having a total thickness within those ranges, depending upon the threat level. It is understood that thickness of lightweight composites may be greater than that of RHA but not necessarily having a greater areal density than RHA.

[0027]A flyer plate 16 is disposed behind the armor plate 14, adjacent the body panel 5 or similar structure that is to be protected. A flyer plate 16 can be made from similar materials and have similar thickness as the armor plate 14. The flyer plate 16 preferably has a thickness of 0.1 to 1, preferably 0.1 to 0.75, preferably 0.125 to 0.5, or preferably about 0.375, inches. It is preferable that the flyer plate 16 has a high elongation to failure value of greater than 5, preferably 8, or preferably 10, %. It is preferably that the flyer plate 16 has a high tensile strength of greater than 40,000, preferably 50,000, preferably 60,000, or preferably 70,000, psi. However, unlike the armor plate 14, which is a continuous sheet of material or materials having an order of armor module dimensions, the flyer plate 16 preferably includes a plurality of discrete plate sections 16a that are attached to one another in a coplanar arrangement to form the flyer plate 16. An exemplary embodiment of the flyer plate 16 is shown in plan view in FIG. 4. In the illustrated embodiment, the plate sections 16a are formed from a single sheet of material, such as RHA, by cutting a series of slits 16b through the plate 16 to provide an array of substantially square plate sections 16a, wherein adjacent plate sections 16a remain attached to one another at their corners. In one embodiment, the slits 16b are provided in the flyer plate 16 so that the discrete plate sections 16a measure approximately 4-inches.times.4-inches. Alternatively, slits 16b can be cut into the flyer plate 16 to provide discrete plate sections 16a having different shapes (e.g. trapezoidal, triangular, hexagonal, etc.) and different dimensions than those mentioned here. In another embodiment, individual sections are spot welded to form an equivalent sheet. Yet in another embodiment, a flyer plate may include a combination of slotted metal plate backed by a ballistic fiber mat so as to reduce possibility of energetic fragment perforating vehicle skin.

[0028]In addition to the elements described above and their materials of construction, another aspect of the disclosed armor architecture is their arrangement and spacing from one another and from the body panel 5 or similar structure to be protected. The flyer plate 16 is preferably spaced from the body panel 5, located 1-3 inches, preferably about 2 inches therefrom. The armor plate 14 is disposed in front of the flyer plate 16, preferably spaced 4-8 inches, preferably about 6 inches from the flyer plate 16 (or about 8 inches from the body panel 5). A representative spacer 30 is shown in the armor architecture of FIG. 10. Spacer materials can be selected so as to cause asymmetric failure. For example, a flyer plate 16 can be supported and spaced from the body panel 5 by spacers 30 located at or adjacent its four corners, all four spacers 30 may not fail identically. Instead, one or several of the spacers 30 may be designed to fail more easily than the remaining spacers 30, so that the flyer plate 16 (or section 16a) is caused to impact the body panel 5 first at one of its edges, or so that the flyer plate (or section) impacts the body panel obliquely, which may further dissipate impact energy. The laminate reactive-armor panels 12 are disposed in front of the armor plate 14 and are the first element that an incoming EFP or other high-energy ballistic projectile will encounter. The number of laminate panels 12 used will depend on a number of factors as will be further described below. In an exemplary embodiment, there are provided 1 to 10 laminate panels 12, more preferably 3-5, more preferably 4 such panels 12. The laminate panels 12 are spaced apart from one another with a distance of 0.125 to 0.5 inch, preferably about 0.25 inch between adjacent panels 12. The panel 12 nearest the armor plate 14 is preferably spaced a distance of 0.5-1 inch therefrom.

[0029]The elements of the armor architecture described above perform complementary functions to protect a body panel 5 from an EFP 4 or other high-energy ballistic threat as will now be described. Additional features and embodiments of the armor architecture 10 and the elements thereof will also be described in conjunction with the following discussion.

[0030]As an EFP 4 or other high-energy ballistic threat approaches the armor 10, it will first encounter the laminate non-explosive reactive armor panels 12. FIG. 5 is a cartoon illustration showing how an exemplary laminate panel 12 behaves as an EFP 4 impacts and passes through it. It is to be recognized that FIG. 5 is a cartoon illustration only, is not necessarily drawn to scale or to be taken literally, and is intended only to provide an idea how the layers 12a and 12b behave on impact of an EFP in conjunction with the following discussion. As seen in FIG. 5, the reactive material of layer 12b begins to volumetrically expand on initial impact of the EFP 4 (FIG. 5a) in response to thermal and kinetic energy delivered by the EFP. This expansion expands and forces outward the outer layers 12a, causing them to continually expand as the EFP passes through. The expansion of outer layers 12a serves to quickly place a non-linear expanding quantity of material in the path of the EFP to deflect, distort, and break-up much of the incoming mass/energy. As a result of the expanding layers 12a, short path-lengths of least resistance are constantly being altered as the EFP proceeds, in directions of lateral movement not directly toward the body panel 5. The reactive material of layer 12b (e.g. polyethylene) sustains the process by propagating the continual expansion by reacting to the incoming energy in a manner that both gasifies and expands the PE, thereby driving the layer 12a expansion and creating hydrodynamic instability in the traveling EFP 4. A schematic diagram is shown in FIG. 5. With each successive encounter with such units, sufficient instability is created so as to tilt and/or break-up EFP from its original direction. As the layers 12a expand, they balloon and distort both toward and away from the incoming projectile. This places new material in the projectile's path, which interrupts the incoming EFP thereby breaking and deflecting much of the material before it can reach the body panel 5. These interactions also absorb energy to slow the remaining portions of the EFP moving towards the body panel 5.

[0031]In the embodiment shown in FIG. 3, the laminate panels 12 are all parallel to one another and arranged at right angles relative to the anticipated trajectory of the EFP 4 on impact. In an alternate preferred embodiment the panels can be provided at an oblique angle relative to the anticipated trajectory of the EFP 4, for example all in parallel as shown in FIG. 6a. The oblique angle can be, for example, 15.degree. to 60.degree., more preferably 30.degree. or 45.degree. relative to the anticipated approach trajectory of the EFP 4. In a still further alternative and preferred embodiment illustrated in FIG. 6b, the panels 12 are provided at alternating and oblique angles relative to the anticipated trajectory of the EFP 4, resulting in the panels 12 being provided at alternating angles relative to one another. In this embodiment, the panels can be provided in the same angles described above (although now alternating) relative to the anticipated trajectory of the EFP. The arrangement of FIG. 6b, wherein the panels 12 are arranged at alternating oblique angles, may be preferred, particularly when the trajectory of the EFP will not be predictably known ahead of time. In the arrangement of FIG. 6b, the expansive-disruptive effect of the panels 12 on the EFP 4 will be realized from alternating angles, which may be more effective to disrupt the trajectory of the EFP and absorb additional energy.

[0032]As will be appreciated, the foregoing effects are compounded each time the EFP encounters a new laminate panel 12 of laminate non-explosively reactive armor. With each successive encounter with a laminate panel 12, additional instability is introduced so as to tilt and deflect and/or break-up the EFP from its original trajectory. Therefore, space and weight permitting, it may be desirable to incorporate multiple such layers. In testing, four such layers composed of aluminum outer layers 12a and a polyethylene reactive layer 12b having thicknesses of 1/8 inch and 1/4 inch, respectively, have been found to be effective in conjunction with the other components as described more fully below. Additional reactive materials that have been successfully tested to perform well in place of PE include natural, un-vulcanized rubber and sulfur. As already mentioned, the laminate panels 12 can be set at zero degrees (perpendicular) to the incoming penetrator and also can be set at a variety of angles to the incoming penetrator. Testing performed at zero- and thirty-degree angles relative to the incoming penetrator demonstrated success to prevent penetration into the body panel 5 in conjunction with the additional armor elements as hereafter described.

[0033]As explained above, each laminate panel 12 is spaced at a select distance from the next. The stiffness of successive panels 12, particularly their respective layers 12a, may be successively increased or decreased to offer increasingly (or decreasingly) compliant structure as the EFP proceeds. This effect may be achieved, e.g., by varying the thickness of the ductile sheets for layers 12a in the direction toward the body panel 5, their composition, or both.

[0034]The armor plate 14 is located behind the laminate panels 12, closer to the body panel 5 as described above. In a preferred embodiment, this plate 14 comprises 3/8-inch thick rolled homogeneous armor (RHA) to absorb the energy of the remaining slug of an incoming EFP 4, or other large or fragmented pieces, after it traverses the laminate panels 12, which by now have absorbed or deflected a proportion of its kinetic energy. The armor plate 14 initiates both deformation and tumbling of the projectile or fragments thereof. As the slug or fragments impact and penetrate the armor plate 14, the energy is even more widely dispersed and more easily absorbed by the armor plate 14 as it tears destructively in penetration of the EFP slug. As it tears, it is believed the aggressive "petalling" of the armor plate 14, preferably RHA, further contacts and impedes the EFP slug, causing it to tumble and further slowing the slug as it continues to approach the body panel 5. It is also possible for the semi-molten mass of copper from the EFP 4 to be dispersed to a great extent upon impact with the armor plate or plates, and in the process create a punched-out disk from the armor plate 14. In such a case, the lengths of projectiles or fragments from the EFP are substantially reduced making it easier to defeat them in successive layer or layers.

[0035]In a preferred embodiment illustrated in FIG. 7, a reinforcing layer 17 (which is preferably a composite layer) is also provided and preferably includes a reinforced sheet of any of the following, or combinations thereof: aluminum, PE, thin RHA, and ballistic E-fiberglass. The reinforcing layer 17 is disposed behind the armor plate 14 (toward the body panel 5) spaced a distance of approximately 1.5 to 2.5 inches, preferably 2 inches therefrom. When this layer 17 is present, it is believed the petalling of the armor plate 14, cooperates with the layer 17 to effectively bound the slug as it emerges from the armor 14, causing it to further fragment and tumble, wherein the layer 17 absorbs and dissipates even more of the remaining kinetic energy in the primary slug and any fragments.

[0036]The final layer of the present embodiment, closest to the body panel 5, is the flyer plate 16, which is preferably a 3/8-inch (0.375 inch) thick steel RHA plate cut to provide 4''.times.4'' or 6''.times.6'' square plate sections 16a as described above, with adjacent sections 16a joined discretely to one another at small regions at their corners. By the time the remaining slug from the EFP 4 penetrates the armor plate 14 and contacts the flyer plate 16, a substantial proportion of its kinetic energy has already been absorbed and dissipated by the elements that came before. The remaining slug, therefore, impacts the flyer plate with substantially reduced kinetic energy compared to the original EFP 4. That slug will impact one of the discrete plate sections 16a of the flyer plate. The impacted plate section 16a will, as a result of the force of impact, be broken free from the adjacent sections 16a to which it is attached only at its corners. The broken-off section 16a will then be forced by the force of the remaining slug, against the body panel 5, resulting in an impact with the body panel 5 across a substantially increased surface area compared to that which would occur from the slug alone. The section 16a of the flyer plate 16 prevents the slug or similar fragment of an EFP from coming into contact with the body panel 5 or similar structure to be protected. The flyer plate 16 construction described above has been shown to take the slug remaining from the EFP 4 following the preceding layers and transfer its momentum to a much larger surface area thereby using the mechanical advantage of dissipating the incoming mass and energy to achieve significant reduction of impact force. For example, a slug of 4 in.sup.2 hitting a flyer plate of 8''.times.8'' is capable of an approximately 16-times reduction in impact-force per area once the flyer plate section 16a impacts the body panel 5. As mentioned above, the flyer plate 16 preferably is disposed approximately 2 inches from the body panel 5 to provide a travel time and space for the optimum effect of momentum and energy dissipation to occur prior to impacting the body panel 5.

[0037]Optionally, additional layers of reinforced composite or other layers may be disposed in the approximately two inches of space between the flyer plate 16 and the body panel 5. Such additional layers may provide additional protection against penetrating the body panel, but will also add weight to the overall armor architecture.

[0038]Against higher-energy EFP threats, additional layers can be added to the architecture specifically to non-explosive reactive armor laminates and armor plate following them.

[0039]Against lower-energy EFP threats, additional weight can be removed from the above architecture by reducing the number of laminate panels 12 and/or the thickness of either or both of the armor plate 14 and flyer plate 16. Alternatively, if tearing or minor penetration of the 3/8'' armor vehicle skin is permitted by the certifying authority, the weight of the overall armor architecture 10 can be reduced by 4 to 6 pounds per square foot given current testing, and still protect occupants against the described threat.

[0040]In a further alternative embodiment, the laminate panels 12 described above can be replaced with a laminate architecture that employs one or several of a variety of geometric patterns so that an incoming EFP's path is intersected by several surfaces at obliquities other than zero. For example, as seen in FIG. 8a the panels 12 may be provided instead as series of concentric, circular metal tubes 22a,22b having the non-explosively reactive material 23 disposed in the annular space defined between concentric circular tubes, wherein the annular space is filled in such a way that there are no gaps or air bubbles to accommodate expanding gases without causing expansion of the two metal surfaces of the concentric circular tubes 22a and 22b. An array of such circular tubes 22a,22b can be disposed in as a layer sandwiched in between opposing outer layers 24 as illustrated. FIG. 8b schematically illustrates an embodiment where four such panels 12 are provided in spaced parallel relationship together with the remaining elements of the disclosed armor architecture. Optionally, each panel 12 may include a plurality of alternating layers of tubes 22a,22b and layers 24, as seen in FIG. 8c. Alternate panels 12 can have the tube 22a,22b arrays oriented at various angles relative to one another (not shown). Yet in another embodiment, a sandwich unit may be constructed out of two parallel corrugated sheets with reactive material in between.

[0041]In another exemplary embodiment, the concentric circular tubes 22a and 22b can be replaced with concentric square- or rectangular-shaped tubes 22c and 22d, as shown in FIG. 9. FIG. 9a illustrates an embodiment wherein concentric square tubes 22c and 22d, having reactive material 23 disposed between, are arranged in arrays sandwiched between opposing outer layers 24. FIG. 9b illustrates another embodiment wherein the concentric square tubes are shown in arrays disposed alternately with alternating layers 24. In still a further embodiment, arrays of concentric tubes, whether rectangular, circular or other cross-section, having reactive material in the annular space there between, can be arranged in a tightly-packed array, with individual layer-arrays of tubes disposed adjacent other individual layer-arrays. FIG. 9c illustrates such an embodiment wherein concentric square-shaped tubes, having reactive material in the space between concentric tubes, are arranged in layer-arrays, with each layer array arranged next to the adjacent layer-arrays in interlocking fashion. In this embodiment, the concentric tubes may be adhered together via an adhesive material, such as polymeric resin, rubber or other material, in the space between the adjacent tubes themselves, or via other suitable means that will be recognized in the art. In all of the embodiments described in this and the preceding paragraph, the layers 24 can be made from any suitable material to bound and retain the tubular arrays in place, for example, aluminum or steel layers, alternatively polymeric or composite (e.g. fiberglass) layers, of relatively low thickness (e.g. about or less than 1/8 inch). It will be appreciated that combinations of the embodiments described in this and the preceding paragraph may also be employed in place of or in conjunction with the laminate panels 12 described previously in the overall armor architecture. In all cases, it is preferred that the material for the tubes themselves be made from a similar ductile material as described above for the layers 12a, and that the reactive material be made of similar material as described above for the layer 12b. Other possibilities include: multiple layers of flat plates set at a certain angle of obliquity, waffle shapes, pyramids, corrugated sheets, etc. There are many possible shapes that can be deployed based on the principles discussed here, and the examples given above are just a few of these possibilities.

[0042]The above-described armor is composed of a hybrid architecture that uses and takes advantage of both reactive armor components (the laminate non-explosive reactive panels 12) and passive armor components (the armor plate 14 and reinforcing layer 17, if present). In addition to these two components, a third novel component is included, the flyer plate 16, which mechanically reduces the impact energy-per-unit-area when the body panel 5 is finally impacted by the EFP 4, or the slug that remains once passing the active and passive components described above. As already described, the flyer plate 16 takes the energy and momentum of that remaining slug and converts it so that instead of impacting the body panel 5 across the remaining (small) cross-sectional area of the slug, it impacts over a much larger (i.e. 16 times or greater) surface area corresponding to the cross-sectional area of the flyer plate section 16a that breaks off and joins the slug to impact the body panel 5. This transfers the remaining kinetic energy and momentum to a larger cross-sectional area, and also lowers the velocity because momentum is conserved when the initial slug now combines with the flyer plate section 16a, which adds substantially to the mass that must be moved by the kinetic energy originally delivered by the slug alone. These effects, when combined with the remaining armor components herein described, have been shown to reliably prevent penetration into an underlying body panel 5 (simulated by 3/8-inch RHA), based on a 460-gram copper EFP propelled by 7.5 lbs of C4 high explosive from a small enclosure at a range of four to eight feet.

[0043]Each of the above elements of the disclosed armor architecture 10 can be prepared via known or conventional methods or techniques. Regarding the laminate panels 12, for example the embodiment illustrated in FIG. 3, these may be manufactured based on known sheet-metal forming techniques wherein two sheets of metal are brought together in a continuous process with the filler material (for layer 12b) provided between them. These laminates can then be used to fabricate the panels 12 as shown in FIG. 3, or used to prepare tubular structures such as those shown in FIGS. 8 and 9. To produce such structures, conventional metal-forming and bending techniques may be used, to provide concentric tubes having the reactive material in between the bend-formed concentric tubes. The resulting concentric tubes then can be arranged in appropriate arrays to provide the desired geometry, for example such as illustrated schematically in FIGS. 8 and 9.

[0044]The flyer plate 16, as described above, is designed to introduce mechanical effects that transfer the momentum and kinetic energy of the remaining slug to a larger mass and greater surface area prior to impacting the body panel 5. The embodiment described above, and illustrated in FIG. 4, is one preferred embodiment. However, the flyer plate 16 need not be perforated to provide discrete flyer plate segments 16a. Instead, it may be a continuous plate so long as appropriate retention structure is provided to hold it in place, and which permits the plate 16 to become destructively disengaged from the retention structure so that it may travel with the remaining slug toward the body panel 5, to thereby increase total mass and decrease energy density on impact. For example, composite spacers 30 (or spacers made of other material that will permit destructive detachment of the flyer plate 16 on impact of the slug) may be used to stand the flyer plate 16 off of the body panel 5 an appropriate distance, e.g. about 2 inches (see FIG. 10).

[0045]In still a further embodiment, the flyer plate 16 can be provided so that the retention structure adjacent one edge of the plate 16 is more easily disrupted or destroyed than adjacent the opposite or other edge. This will have the effect that on impact of the slug, the flyer plate 16 will be more readily broken away at one edge, causing it to swing or hinge relative to the retention structure that remains temporarily intact. This embodiment may have the impact of further attenuating impact energy.

[0046]Now referring to FIG. 10, the armor architecture 10 described above can be provided in modular form so that it can be easily attached to, and replaced from, a body panel 5, for example once a particular module or modules have been damaged, either by EFP-impact or otherwise. In FIG. 10, the laminate non-explosive reactive panels 12 are enclosed within a first enclosure 40 to provide a first armor module 42, and the remaining elements (armor plate 14, reinforcing plate 17 and flyer plate 16) are enclosed within a second enclosure 50 to provide a second armor module 52. In the illustrated embodiment, the second module 52 is secured to and supported on the body panel 5 via a pair of complementary hook elements 55 and 56 that support the weight of the module 52 from the top, and a conventional interference-fit ball-and-socket connection 58 at the bottom of the module 52. In the illustrated embodiment, spacers 30 are located within the enclosure 50 and stand flyer plate 16 off from the body panel 5 the desired distance. This results in the module 52 appearing essentially as a cube from the outside, with appropriate hook- or other suitable fasteners to support it on the body-panel 5 surface. If additional reinforcing layers (e.g. polymer, fiberglass or other layers) are to be disposed between the flyer plate 16 and the body panel 5 (e.g. layers 19 as illustrated in FIG. 7), it is preferred that additional reinforcing layers be provided within the enclosure 50 in the stand-off space created by the spacers 30. Such additional reinforcing layers may include, e.g., RHA, aluminum alloys, fiber-reinforced polymers and polymer composites, ballistic-fiber cloths such as Kevlar weaves, etc. Alternatively, the spacers 30 may be located outside of the enclosure 50. The enclosure 50 may be provided by simply wrapping a thin sheet of aluminum or other suitable material around the circumference of the respective layers, so that front face 54a represents the front face of the armor plate 14, and the rear face 54b represents either the rear face of the flyer plate 16 if the spacers are located outside the enclosure 50 (embodiment not shown), or a thin sheet of metal provided to seal the enclosure 50 and the resulting module 52.

[0047]The first module 42 is provided similarly as the second module 52 mentioned above, and is secured to the front face 54a of the second module 52 by suitable hook-type and ball-and-socket type fasteners as illustrated, or other suitable fasteners known or conventional in the art. For example, the fasteners for both the first and second modules 42 and 52 can be, e.g, screw-type fasteners, sliding fasteners that employ a lock-in-place mechanism such as clips or other appropriate structure.

[0048]As will be appreciated, this modular construction will have certain advantages. For example, if the first module 42 is damaged by small arms fire that otherwise cannot penetrate the armor plate 14, then only the first module 42 may be replaced leaving the second module 52, which was undamaged, in place. Alternatively, if both modules 42 and 52 are damaged such as by an EFP, then both modules may be removed and replaced on the underlying and substantially un-damaged body panel 5. It will further be appreciated that other plates, elements and other armor components, including those described above, may also be incorporated into the modules 42 and 52 when and where desired depending on the specific threat to be defeated, space- and weight-constraints permitting.

[0049]Within each module 42 and 52, the individual elements and layers may be spaced apart from one another by suitable spacers, not shown. Alternatively, other spacing elements may be used. For example, all of the panels may be drilled to provide concentrically-aligned through-bores, through which a bolt is provided to secure each layer in place at the appropriate spacing, for example using nuts threaded onto the long bolts. Selection of particular structure or spacers to achieve the desired spacing is well within the ability of the person of ordinary skill in the art. In certain embodiments, plates and layers disclosed herein may be curved and not truly planar. For example, the armor plate 14 and/or the flyer plate 16 may have a curved surface to further deflect the incoming EFP 4 or remaining slug.

[0050]A substantial advantage of the embodiments disclosed herein is that they are capable to defeat a significant EFP threat at significant weight savings compared to conventional armors required to defeat equivalent threats. For example, the architecture described above, weighing approximately 45 pounds per square foot, represents a weight-savings of approximately 68% compared to the equivalent RHA-alone armor that would be required to defeat an equivalent threat (460-gram copper EFP produced from bowl-shaped copper plate of the same weight by detonating 7.5 lbs. of C4 high explosive in a small, closed-end container at a range of four to eight feet).

[0051]As will be appreciated from the foregoing description, the present armor architecture in a preferred embodiment includes at least three basic components: A) laminate non-reactive armor panels 12, B) at least one layer of armor plate 14 that can be similar to conventional RHA armor and C) at least one flyer plate 16 that is positioned a distance (preferably 2 inches) from the body panel 5 to be protected to transfer the momentum of any remaining incoming mass to a much broader surface area prior to impacting the body panel 5, which may reduce as much as 16 times the force/momentum per area of impact, which improves survivability of the body panel 5. It is believed certain of the individual components (A), (B) and (C) mentioned above may be capable on their own, or in combinations of only two of them, to stop individual classes of threats. As it will be shown in one of the examples, if component A manages to reduce the kinetic energy of EFP to a sufficient level, then only component C may be sufficient to protect the vehicle. However, it is believed that the combination of all three is necessary reliably defeat the wide variety of threats that battlefield vehicles typically encounter in modern guerrilla warfare, for example the EFPs described above, RPG-style shaped charges as well as ballistic threats including 50-caliber AP and 14.5 AP rounds.

[0052]In order to promote a further understanding of the invention, the following examples are provided. These examples are shown by way of illustration and not limitation.

Example 1

[0053]An armor architecture consisting of 7 layers of laminate non-reactive panels 12 each consisting of two 1/8'' aluminum plates (12a) sandwiching a 1/4'' LDPE (low density polyethylene sheet) (12b) arranged in a zig-zag manner (shown in FIG. 6b), followed by a flyer plate 16 consisting of 3/8'' RHA, which all together weighed approximately 47 (+/-2) pounds per square foot, has been shown to defeat an EFP threat provided in the form of 460 grams of copper propelled from an EFP device by 7.5 lbs. of C4 high explosive when the armor was placed with the flyer plate 16 spaced at 4.5 feet from a 3/8-inch thick RHA panel to simulate the skin (body panel 5) of a typical armored military vehicle. High speed photography was used determine that the velocity of the EFP was in the range of 2.2 to 2.6 km/sec. In testing with these parameters, the 3/8-inch thick RHA skin exhibited no perforation and only a small indentation less than 1/8 inch deep. As a comparison, the identical threat penetrated approximately 3.5'' of conventional RHA, i.e., having areal density of about 140 lbs/ft.sup.2. Therefore a significant savings (-66%) in areal density was realized while still providing effective protection against the EFP. This comparative example shows that if a threat is calibrated in terms of areal density of RHA needed to defeat it, then an armor solution according to this invention can be provided and modified according to the present teachings to defeat the threat at substantial weight savings compared to conventional RHA, making it more practical to up-armor vehicles.

Example 2

[0054]An armor arrangement was constructed as follows: five laminate non-reactive panels 12 were constructed in such a way that each panel 12 consisted of two 1/8'' aluminum plates (Alloy 6061) (12a) with a 1/4'' polyethylene sheet (12b) in intimate contact. The panels 12 were spaced approximately 1/2'' apart and were oriented at roughly an 11-degree angle with respect to the horizontal plane of the following armor plate consisting of a 3/8'' RHA plate (14) and 1/2'' fiberglass composite (.about.70 vol % E-Glass). A gap of about 1.5'' between the RHA plate and the composite. A flyer plate made of 3/8'' RHA was disposed behind the armor plate and spaced at 2'' from the vehicle skin to be protected. The overall area density of this arrangement was about 58 lbs/ft2. The EFP threat was identical to Example 1. Projectile was aimed at zero obliquity with respect to the armor plate and the flyer plate. The vehicle skin consisted of 3/8''RHA plate as an outer layer, 2'' fiberglass composite in the middle and 1/4'' RHA plate representing interior of the vehicle. After the test, the outer skin layer was dented but not perforated thus preventing any damage to the interior. Compared to an RHA armor panel alone, the weight savings was about 59%. One advantage of the armor arrangement in Example 2, over that of Example 1, was in the spacing of the armor components. While in Example 1, the armor arrangement exceeded a target depth of 12'', it was less than 12'' in Example 2. This contrast illustrates the relationship between areal density and compactness of the solution and that the armor architecture described herein is versatile enough to allow an armor designer to tailor the solution to a specified set of constraints.

Example 3

[0055]An armor architecture according to Example 2 was constructed except only four panels (12) were used instead of five. As a result, the areal density of this armor arrangement was reduced to about 53 lbs/ft2. The EFP threat was identical to Example 1. After the test, the outer skin of the vehicle was damaged or punctured, the 2'' fiberglass panels showed cracking, and there was no damage to vehicle's interior plate. As compared to an RHA armor panel alone, weight savings was about 62%. As seen in this and the above Examples, there is a relationship between the areal density of the armor architecture and the acceptable level of damage to the vehicle skin.

Example 4

[0056]The armor architecture of Example 2 was tested against a RPG surrogate and 0.50 Cal M2 AP rounds fired at about 2700'/sec. The RPG surrogate was a rock perforator used in oil industry (Owen Oil Tools Model: Raptor SDP-5000-400). This was tested against RHA plate to provide a benchmark. The critical areal density of the RHA plate needed to defeat this perforator was about 325 psf (or slightly greater than 8 inch thick RHA steel). The armor architecture of Example 2 was able to defeat the RPG surrogate completely and the outer vehicle remained totally unaffected. Similar results were obtained when tested against 0.50 Cal M2 AP round. These test show that the armor architecture described herein is capable of defeating multiple types of high-energy threats, such an EFP, a RPG surrogate and a 0.50 Cal M2 round. It is understood that the armor architecture arrangement will differ depending upon the lethality of the threat level.

[0057]While the invention has been described with respect to certain exemplary embodiments, it will be appreciated that various modifications can be made thereto by the person having ordinary skill in the art having reviewed the present disclosure, without departing from the spirit and the scope of the invention as set forth in the appended claims.

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