Light-weight vehicles are being subjected to a growing and significant problem, Explosively Formed Projectiles (EFPs). Originally reactive armor was designed to defeat anti-tank rounds. These rounds use a conical shape charge capable of producing a high temperature jet delivering a tremendous amount of energy on a single point. EFPs are highly dense solid matter traveling at 7,000 to 8,000 fps with very high kinetic energy making it much harder to stop using a flying plate method.
Stopping a Projectile
The basic concept in stopping a projectile is that work must equal energy. The more work the armor can do on the projectile, the more kinetic energy it can absorb. Conventional armor augments work by increased frictional force through hardness, tensile strength and thickness of the armor system.
Normal force is what gives rise to the friction force, the magnitudes of these forces being related by the coefficient of friction “μ” between the two materials:
f=μN
Therefore, given the mass and velocity of the projectile a simple equation would define the thickness “d” and “f” force to stop the projectile.
The hydrodynamic impact of an EFP delivers an enormous amount of energy. In the past, stopping an EFP has been directly related to the density of the armor. It has always been a balance between weight and thickness. The current solution of using rolled homogeneous armor (RHA) backing with Polyethylene and other composites is not a viable solution for light-weight vehicles. For example, to defeat a 135 mm EFP the required armor would be 12-16 inches thick and 80-120 lbs/psf. Using this logic to stop the current threat the minor system would need to be more then 21 inches thick.
Conventional reactive armor systems are omni-directional thus, the back pressure is rather significant. When designing a proactive armor for light-weight vehicles, the back pressure is a major factor to consider.
Embodiments of a reactive armor may include reactive armor that includes multiple layers is described herein. The reactive armor may include a self-healing outer layer, a ceramic tile layer and a backing layer. The ceramic tile layer may include a plurality of ceramic tiles and explosive material. The ceramic tiles may be hexagonal. The ceramic tiles may each define a hollow space in which the explosive material is deposited. The reactive armor may be combined with non-reactive armor.
Embodiments of reactive armor that includes multiple layers is described herein. The reactive minor may include a self-healing outer layer, a tile layer and a backing layer that may be affixed to the tile layer. The tile layer may include a plurality of tiles, each defining one or more hollow spaces, and explosive material that at least partially fills hollow spaces in the plurality of tiles. The tiles may be ceramic tiles and may be hexagonal in shape.
The detailed description will refer to the following drawings, wherein like numerals refer to like elements, and wherein:
Diagram 1 illustrates a bullet entering a piece of armor.
Described herein are embodiments of an armor system and method for defeating armor piercing rounds, EFPs, RPGs and other threats to personnel, vehicles, buildings and property. In bridging the gap between conventional reactive armor systems and the need to minimize back pressure, embodiments provide a focused, directional system that results in little back pressure using a minimal amount of explosive but still provides protection against EFPs. Embodiments provide a new armor system designed for light-weight armored vehicles that is both passive and reactive to defeat armor piercing rounds as well as EFPs. This armor is based on Magmacore™ armor technology that uses a unique 3D matrix for displacing energy as well as several patent pending related applications. See, e.g., the '761 patent and the other cross-referenced applications above.
Embodiments described herein are designed to defeat EFPs by using counter measure shape charges, focusing a tremendous amount of kinetic energy at the point of contact. In various embodiments, armor materials are engineered to be consumed in the reaction of defeating an EFP, thus minimizing secondary fragmentation. Performance Canabilities:
Embodiments described herein provide an armor system that is both passive and reactive and which has the following characteristics:
Building on the Magmacore™ armor concept of a 3D matrix for displacing energy, the embodiments described herein provide a viable armor to defeat EFPs and other threats. Embodiments described herein have a unique three-dimensional rigid core designed for structural integrity and to displace energy. This design includes a three-prong approach to defeat EFPs; (1) disrupt the EFP, (2) deliver a focused energy “shape charge” and (3) absorb the resulting shock.
Embodiments of the reactive armor described herein provide a passive and reactive armor system, all-in-one, developed specifically for light armored vehicles. Some additional advantages of reactive armor system embodiments are: it is scalable for a range of threats, has flat and curved surfaces, is lightweight, and has a low profile.
With reference now to
In the embodiment shown, the explosive material 104 is pentaerythritol tetranitrate (PETN). In the embodiment shown in
It is also important to note that ceramic tiles 100 may be sized larger or smaller depending on the nature of the expected threats. If more explosive material 104 and larger ceramic tiles 100 are needed to provide effective static armor functionality, larger ceramic tiles 100 may be used.
In the reactive armor, the explosive material 104 reacts to an EFP, or other threat such as an RPG, to deliver focused energy (a shape charge), disrupting the EFP affects. Ceramic tiles 100 may be made of virtually any three-dimensional shape, such as cubes, cylinders, spheres, etc. The tiles may be made out of various materials, other than ceramics, and filled with other materials, such as sand.
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In
Ceramic tile 200 shown in
Ceramic tile 200 shown in
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Self-healing layer 322 may be deposited on top of and help contain ceramic tile layer 324. Ceramic tile layer 324, as described above, may include ceramic tiles 300 with explosive 304 deposited along the side walls 306. As described above, ceramic tile layer 324 may include a single layer of ceramic tiles 300 or multiple layers of ceramic tiles 300 stacked on top of one another. Ceramic tiles 300 may be arranged within each layer as shown in
Reactive armor 320 may also include a backing layer 326. Backing layer 326 may provide backing and additional static armor functionality of reactive armor. Backing layer 326 may also provide protection from reactive armor affects on non-threat side of reactive armor 320. See the '761 patent or the other cross-referenced patent applications for description of backing layers. Backing layer 326 may be made from a variety of materials (e.g., steel, plastic, composite, wood, Magmacore™ armor as described in the '761 patent or the other cross-referenced patent applications) and may be secured to the tiles with an epoxy. Different tiles, such as those shown in
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Reactive armor 920 may include a ceramic tile layer 924 and a backing layer 926. Reactive armor 920 may also include a self-healing layer, which is not shown in
Various testing, as illustrated and described in the '851 application, was performed on embodiments of the reactive armor described herein. During testing, embodiments of the reactive armor were able to greatly reduce the depth and width of the cut from various explosions, such as a 5400 grain Liner Shape Charge (LSC) (used to minimize the possibility of skewing the tests used a 5400 grain linear shape charge known for its' consistency). The unimpeded Liner Shape Charge cut into the RHA the furthest. The 2 mm Dura Sheet Explosive did help reduce the depth and width of the cut, but with great back pressure. Increasing the Dura Sheet Explosive to 6.4 mm did not improve the results from 2 mm of Dura Sheet Explosive, however the back pressure was so great that it deformed the 1¼ steel. In this case the Dura Sheet Explosive actually was helping the LSC.
The best result achieved was using ceramic tiles with 2 grams of Dura Sheet Explosive per ceramic tile. See the table and graph below
In developing the reactive minor, testing was conducted to confirm the structure of the ceramic layer or core provides protection to the explosive and that the reactive armor embodiments is stable in non-EFP conditions. The strain tests performed determined that reactive minor, with ceramic tiles filled with explosive material, would not detonate from the affects of a non-EFP/RPG impact. See the '851 application.
A pinch test was also performed to see if the ceramic tiles filled with explosive material would detonate and the result was no detonation. The ceramic tiles contained the explosive from redundant detonation in this pressure test. See the '851 application.
Additional tests were performed to determine if reactive armor with ceramic tiles filled with explosive material would detonate from the affects of small arms fire. The result was no detonation. Another test was conducted to determine structural performance and the result was that the reactive armor with ceramic tiles filled with explosive material contained the explosion from the redundant detonation with ½ lbs of PETN.
Various embodiments of reactive armor and various combinations of the reactive armor embodiments described herein may be used to address a threat from EFPs, RPGs and threats. For example, multiple layers of reactive armor embodiments described herein may be used. Layers of reactive armor combined with layers of armor described in the '309 application, the '663 application, and/or the '761 patent. Such combinations may be configured, for example, as described in '309 application, the '663 application, and/or the '761 patent. One of the many advantages of the reactive armor, armor described in the '309 application, the '662 application, and/or the '761 patent, is that it may be designed to address virtually any threat.
The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention as defined in the following claims, and their equivalents, in which all terms are to be understood in their broadest possible sense unless otherwise indicated.
This application claims the priority of U.S. Provisional Application Ser. No. 61/064,851, entitled “Reactive Armor System and Method,” (“the '851 application”) which was filed Mar. 31, 2008 and is incorporated herein by reference. This application is also a continuation-in-part of U.S. patent application Ser. No. 11/979,309, now U.S. Pat. No. 7,628,104, entitled “Methods and Apparatus for Providing Ballistic Protection,” filed Nov. 1, 2007 (“the '104 patent”) and U.S. patent application Ser. No. 11/978,663, entitled “Apparatus for Providing Protection From Ballistic Rounds, Projectiles, Fragments and Explosives,” filed Oct. 30, 2007 (“the '663 application”), which are a continuation and continuation-in-part, respectively, of U.S. patent application Ser. No. 11/296,402, now U.S. Pat. No. 7,383,761, entitled “Methods and Apparatus for Providing Ballistic Protection,” (“the '761 patent”). The above applications and patents are all incorporated herein by reference.
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Number | Date | Country | |
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20120000352 A1 | Jan 2012 | US |
Number | Date | Country | |
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61064851 | Mar 2008 | US |
Number | Date | Country | |
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Parent | 11979309 | Nov 2007 | US |
Child | 12385126 | US | |
Parent | 11978663 | Oct 2007 | US |
Child | 11979309 | US | |
Parent | 11296402 | Dec 2005 | US |
Child | 11978663 | US |