CA2768944A1

CA2768944A1 - Apparatus and method for defeating high energy projectiles

Info

Publication number: CA2768944A1
Application number: CA2768944A
Authority: CA
Inventors: Vernon P. JOYNT; Robert A. Cole; Thomas E. Borders, Iii; Gregory W. Engleman
Original assignee: Force Protection Technologies Inc
Current assignee: Force Protection Technologies Inc
Priority date: 2009-08-03
Filing date: 2010-08-02
Publication date: 2011-05-05
Also published as: GB201202520D0; WO2011053399A3; AU2010313732A1; GB2484450A; WO2011053399A2

Abstract

The present disclosure is directed to an armor system for protecting a vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull. The armor system has a modular armor subsystem configured to be mounted exterior to the vehicle hull. The modular armor subsystem has a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory, and a first intermediate sheet-like layer, the layer including low density material of a density less than metal, located between the leading layer and the hull. The modular armor subsystem also has a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull, and a dispersion area located between the first and the second intermediate sheet- like layers. The density of the low density leading layer material is less than the density of the first intermediate layer low density material, and the density of the second intermediate layer material is greater than the density of the first intermediate layer low density material.

Description

APPARATUS AND METHOD FOR
DEFEATING HIGH ENERGY PROJECTILES
Cross Reference to Related Application [001] This application claims the benefit of U.S. Provisional Application No.
61/213,963, filed August 3, 2009, which is herein incorporated by reference in its entirety.

Technical Field [002] The present disclosure relates to an armor system that resists penetration by projectiles.

Background [003] Conventional armor may be subjected to a variety of projectiles designed to defeat the armor by either penetrating the armor with a solid or jet-like object or by inducing shock waves in the armor that are reflected in a manner to cause spalling of the armor such that an opening is formed and the penetrator (usually stuck to a portion of the armor) passes through the armor, or an inner layer of the armor spalls and is projected at high velocity without physical penetration of the armor.

[004] Some anti-armor weapons are propelled to the outer surface of the armor where a shaped charge is exploded to form a generally linear "jet" of metal that will penetrate solid armor. Such weapons are often called Hollow Charge ("HC") weapons. A rocket propelled grenade ("RPG") is such a weapon. An RPG 7 is a Russian origin weapon that produces a penetrating metal jet, the tip of which hits the target at about 8000m/s. When encountering jets at such velocities, solid metal armors behave more like liquids than solids. Irrespective of their strength, they are displaced radially and the jet penetrates the armor.

[005] Various protection systems are effective at defeating HC jets.
Amongst different systems, the best known are reactive armors that use explosive in the protection layers that detonate on being hit to break up most of the HC
jet before it penetrates the target. Such systems are often augmented by what is termed "slat armor," a plurality of metal slats disposed outside the body of the vehicle to prevent the firing circuit of an RPG from functioning.

[006] A second type of anti-armor weapon uses a linear, heavy metal penetrator projected at a high velocity to penetrate the armor. This type of weapon is referred to as EFP (explosive formed projectile) or SFF (self forming fragment), sometimes referred to as a "pie charge" or a "plate charge."

[007] In some of these weapons the warhead behaves as a hybrid of the HC and the EFP and produces a series of metal penetrators projected in line towards the target. Such a weapon will be referred to herein as a Hybrid warhead.
Hybrid warheads behave according to how much "jetting" or HC effect the hybrid warhead has, and up to how much of a single, large penetrator-like EFP it produces.

[008] Another type of anti-armor weapon propels a relatively large, heavy, generally ball-shaped solid projectile (or a series of multiple projectiles) at high velocity. When the ball-shaped metal projectile(s) hits the armor, the impact induces shock waves that reflect in a manner such that a plug-like portion of the armor is sheared from the surrounding material and is projected along the path of the metal projectile(s), with the metal projectile(s) attached thereto. Such an occurrence can, obviously, have very significant detrimental effects on the systems and personnel within a vehicle having its armor defeated in such a manner.

[009] While the HC type weapons involve design features and materials that dictate they be manufactured by an entity having technical expertise, the latter type of weapons (EFP and Hybrid) can be constructed from materials readily available in a combat area. For that reason, and the fact that such weapons are effective, these weapons have proven troublesome to vehicles using conventional armor.

[010] The penetration performance for the three mentioned types of warheads is normally described as the ability to penetrate a solid amount of RHA
(Rolled Homogeneous Armor) steel armor. Performances typical for the weapon types are: HC warheads may penetrate 1 to 3 ft thickness of RHA; EFP warheads may penetrate 1 to 6 inches of RHA; and Hybrids warheads may penetrate 2 to 12 inches thick RHA. These estimates are based on the warheads weighing less than 15 lbs and being fired at their respective optimal stand off distances. The diameter of the holes made through the first inch of RHA would be: HC up to an inch diameter hole; EFP up to a 9 inch diameter hole; and Hybrids somewhere in between. The respective optimal stand off distances for the different charges are:
an HC charge is good under 3 feet, but at 10 ft or more it is very poor; for an EFP
charge a stand off distance up to 30 feet produces almost the same (good) penetration and will only fall off significantly at very large distances such as 50 yards; and for Hybrid charges penetration is good at standoff distances up to 10 ft, but after 20 feet penetration falls off significantly. The way these charges are used is determined by these standoff distances and the manner in which their effectiveness is optimized (e.g., the angles of the trajectory of the penetrator to the armor). These factors affect the design of the protection armor.

[011] While any anti-armor projectile can be defeated by armor of sufficient strength and thickness, extra armor thickness is heavy and expensive, adds weight to the armored vehicle using it, which, in turn, places greater strain on the vehicle engine and drive train, and thus has a low "mass efficiency." Additionally, reactive armor, i.e. armor that exhibits an active reaction to an anti-armor projectile, such as a counter explosive or electric charge, can be dangerous to handle and expensive.
Traditional non-explosive reactive armor ("NERA") may sandwich rubber with metal plates. While this is less dangerous to handle than explosive reactive armor, it may still be expensive and still add excessive weight.

[012] Armor solutions that offer a weight advantage against these types of weapons can be measured in how much weight of RHA it saves when compared with the RHA needed to stop a particular weapon penetrating. This advantage can be calculated as a protection ratio, the ratio being equal to the weight of RHA
required to stop the weapon penetrating, divided by the weight of the proposed armor system that will stop the same weapon. Such weights are calculated per unit frontal area presented in the direction of the anticipated trajectory of the weapon.

[013] Thus, there exists a need for an armor that can defeat the high energy projectiles (i.e., projectiles having velocities of greater than about 2500m/s) from anti-armor devices without requiring excess thicknesses of armor, and thus have a high mass efficiency. There also exists a need for an armor to behave similarly to NERA without the added weight or expense of traditional NERA. Such armor may be made of materials that can be readily fabricated and incorporated into a vehicle design at a reasonable cost, and may be added to existing vehicles.

[014] The present disclosure is directed to overcoming shortcomings and/or other deficiencies in existing technology.

Summary of the Disclosure [015] The present disclosure is directed to an armor system for protecting a vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull. The armor system includes a modular armor subsystem configured to be mounted exterior to the vehicle hull. The modular armor subsystem includes a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory, and a first intermediate sheet-like layer, the layer including low density material of a density less than metal, located between the leading layer and the hull. The modular armor subsystem also includes a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull, and a dispersion area located between the first and the second intermediate sheet-like layers. The density of the low density leading layer material is less than the density of the first intermediate layer low density material, and the density of the second intermediate layer material is greater than the density of the first intermediate layer low density material.

Brief Description of the Drawings [016] Fig. 1 is a schematic, cross-sectional view of a first exemplary disclosed armor system;

[017] Fig. 2 is a schematic, cross-sectional view of an alternative arrangement of the armor system of Fig. 1;

[018] Fig. 3 is a schematic, cross-sectional view of a second exemplary disclosed armor system;

[019] Fig. 4 is a schematic, cross-sectional view of an alternative arrangement of the armor system of Fig. 3;

[020] Fig. 5 is a schematic, cross-sectional view of a first exemplary disclosed vehicle using the armor system of Fig. 1;

[021] Fig. 6 is a schematic, cross-sectional view of a third exemplary disclosed armor system;

[022] Fig. 7 is a schematic, cross-sectional view of an alternative arrangement of the armor system of Fig. 6;

[023] Fig. 8 is a schematic, cross-sectional view of a fourth exemplary disclosed armor system;

[024] Fig. 9 is a schematic, cross-sectional view of an alternative arrangement of the armor system of Fig. 8 [025] Fig. 10 is a schematic, cross-sectional view of a second exemplary disclosed vehicle using the armor system of Fig. 6.

Detailed Description [026] Fig. 1 illustrates an exemplary disclosed armor system 10 for protecting a vehicle 11 (shown in Fig. 5) from projectiles such as, for example, HC, EFP, and Hybrid warheads. In the following discussion, the projectile has an expected trajectory 12 relative to vehicle 11. Trajectory 12 establishes a direction for understanding certain terms used in the following discussion (e.g., "leading,"
"rear," "behind," "front," etc.) for describing the components of armor system 10 that the projectile successively confronts as it approaches a vehicle hull 28.
Moreover, the terms "exterior" and "interior," as used in conjunction with the vehicle hull 28, are given their usual meanings (i.e., "exterior" is outside of hull 28 relative to trajectory 12, and "interior" is inside of hull 28 relative to trajectory 12).

[027] In general, the direction of threat projectiles is presumed to be along trajectory 12, which is substantially perpendicular to an exterior surface of a vehicle hull, because the substantially perpendicular trajectory imparts the full momentum of the projectile to the vehicle (where full momentum is desired by an aggressor who fires a projectile at the vehicle). In contrast, a projectile that impacts a vehicle at a substantially non-perpendicular trajectory, with respect to a hull exterior surface, may glance off of the vehicle hull and not impart the full momentum of the projectile. However, it is contemplated that the benefits of the system described below may also apply to projectiles fired at a substantially non-perpendicular trajectory, relative to an exterior surface of a vehicle hull.

[028] Armor system 10 may include an exterior armor subsystem 16 and an interior armor subsystem (not shown). Exterior armor subsystem 16 may be configured to reduce the speed of high energy projectiles, i.e. speeds of over m/s, to the speed of traditional projectiles, i.e. speeds under 1000 m/s, before the projectile contacts the conventional armor of vehicle 11. In order to reduce the speed of the projectile, exterior armor subsystem 16 may include a series of layered materials, where the outermost layer is a relatively lower density material and the innermost layer is a relatively higher density material. In this manner, exterior armor subsystem 16 may include a leading sheet-like layer 20. Layer may include a material of a density that is lower than metal. Exterior armor subsystem 16 may also include an intermediate sheet-like layer 22 including a low density plastic or rubber, where a front surface 22a of layer 22 may abut a rear surface 20b of layer 20. Exterior armor subsystem 16 may further include an intermediate sheet-like layer 26. Layer 26 may include a metal, a low density material, or a combination of these materials. A dispersion space 24, or "air gap,"
may be disposed between a rear surface 22b of layer 22 and a front surface 26a of layer 26. Alternatively, a front surface 26a of layer 26 may abut rear surface 22b of layer 22. A rear surface 26b of layer 26 may abut a front surface 28a of vehicle hull 28.

[029] Leading layer 20 may include a low density material having a density greater than air, but lower than metal such as, for example, a foam material.
For example, layer 20 may include a low density polypropylene composite material.
Specifically, layer 20 may include Tegris , available from Milliken & Company, Milliken Road, P.O. Box 1926, Spartansburg, South Carolina 29303 USA. It is also contemplated that layer 20 may include materials selected from one or more low density materials such as, for example, Kevlar reinforced polymer or plastics, polyethylene composites, and hybrid materials formed from one of these alternative low density materials. For example, layer 20 may be Dyneema , available from DSM, Dyneema, Mauritslaan, Urmond, P.O. Box 1163, 6160 BD Geleen, The Netherlands. One skilled in the art, given the present disclosure, may be able to search out and select other low density materials having similar properties to these exemplary materials. These exemplary materials have been found to help attenuate the high velocity jets of metals that may accompany high energy projectiles, and thus increase the chance of defeating such threats. Layer 20 may have a thickness, for example, of between about 6" and about 14".

[030] Alternatively, leading layer 20 may include a glass fiber material such as, for example, R-Glass composite in phenolic resin, for example ShieldStrandTM

that may be obtained from OCV Reinforcements, 1 Owens Corning Parkway, Toledo, OH 43659. For example, layer 20 may include QuicksilverTM, available from AGY, 2556 Wagener Road, Aiken, SC 29801. It is also contemplated that layer 20 may include an S-Glass material such as, for example, S-2 TM and FeatherlightTM, available from AGY. It is further contemplated that layer 20 may include E-Glass composite material available from AGY. It is further contemplated that layer 20 may include composite materials such as, for example, a Kevlar reinforced polymer material that may be infused with phenolic resin, a Kevlar woven blanket material including a plurality of plies that may be woven together, or a polyethylene composite material. It is also contemplated that layer 20 may include a carbon fiber woven blanket material. It is also contemplated that layer 20 may include any hybrid composite of the above systems.

[031] Intermediate layer 22 may include a low density rubber or plastic.
Low density rubber or plastic may include, for example, ABS, acrylic, acetal (Delrin), butyl, elastomers, fluoroplastics, garolite, latex, natural gum rubber, neoprene, noryl, nylon, PEEK, PBT, PET, polyamide, polycarbonate, polystyrene, polyethylene (LDPE, HDPE, UHMWPE), polypropylene, polypropylene oxide, polyurea, polyurethane, santoprene, silicone, sorbothane, urethane, and viton.
It is contemplated that any low density plastic known in the art would be suitable.
It is further contemplated that any portion of the low density rubber or plastic may be recycled material. Layer 22 may have a thickness of between about 1" and about 8".

[032] Intermediate layer 26 may include a metal such as, for example, a high strength aluminum alloy having a tensile strength greater than 20,000 lbs./in.2 and an elongation to break greater than 10%. Therefore, layer 26 may have a relatively high elongation at tensile rupture. Layer 26 may include high strength aluminum alloys such as, for example, 7039 aluminum, 5083 aluminum, 6061 aluminum, and 2024 aluminum. It is also contemplated that layer 26 may include one or more of materials such as, for example, high strength aluminum, copper, steel, stainless steel, magnesium, molybdenum, copper, zirconium, titanium, and nickel. Layer 26 may have a thickness, for example, of between about 1/2" and about 2".

[033] Alternatively, it is contemplated that intermediate layer 26 may be a similar material as layer 20 described above. Further, layer 26 may include a combination of the metal material described above as well as a similar low density material as layer 20.

[034] Dispersion space 24 may be a space between rear surface 22b of layer 22 and front surface 26a of layer 26, and may be measured in a direction generally perpendicular to parallel-aligned layer 22 and layer 26. Layer 22 may be spaced from layer 26, for example, by mechanical spacers and/or a low density foam-like material. Accordingly, dispersion space 24 may be a substantially empty space maintained via mechanical spacers, or may be substantially filled with foam-like material. It is also contemplated that both mechanical spacers and foam-like material may be disposed within dispersion space 24. The foam-like material may be any suitable foam material such as, for example, material meeting the FMVSS
302 Burn Rate Test such as EL Foam P300 and P600, available from Elliott Co., 9200 Zionsville Road, Indianapolis, Indiana 46268.

[035] Dispersion space 24 may serve to allow significant lateral dispersion of projectile material passing therethrough, thereby impeding the penetration of the projectile material through armor system 10 in the direction of trajectory 12, and may contain a portion of the projectile material within dispersion space 24.
The term "lateral" indicates a direction at an angle from the initial line of flight of the projectile (i.e. trajectory 12). As the moving material of the projectile is increasingly dispersed within dispersion space 24, the energy that the projectile exerts incident to the next successive layer (e.g., hull 28) becomes increasingly less concentrated.
In addition, as the thickness of the dispersion space increases, the kinetic energy per surface area that is imparted to the successive layer (e.g., layer 26) decreases.
Dispersion space 24 may have a width, for example, of between about 1" and about 6", allowing dispersion space 24 to transversely distribute significant amounts of kinetic energy, without resulting in an impractical overall thickness of armor system 10. Thus, dispersion space 24 may effectively lower the kinetic energy per surface area that is imparted to the successive layer.

[036] Vehicle hull 28 may include a high strength steel such as, for example, a 500 Brinell hardness steel. For example, hull 28 may include Mil A-46100 Armor Plate. Hull 28 may have a thickness, for example, of between about 1/4" and about 2". An additional layer of metal (not shown), similar to layer 26, may be disposed between hull 28 and layer 26. Vehicle 11 may include any suitable interior armor system known in the art.

[037] Exterior armor subsystem 16 of Fig. 1 may be permanently mounted to hull 28, may be part of a modular system that may be easily removed from hull 28, or a portion of exterior armor subsystem 16 may be permanent and a portion may be modular. Layers 20, 22, and 26 may be attached to each other by any suitable method such as, for example, via adhesive having relatively high strength and relatively high elongation to break. For example, methacrylate adhesive, or any other suitable adhesive having high strength and high elongation to break, may be applied to the abutting surfaces to attach layers 20, 22, and 26 to each other.
Adhesive may be applied to surfaces 20b and/or 22a to attach leading layer 20 to intermediate layer 22, and to surfaces 22b and/or 26a to attach intermediate layer 22 to intermediate layer 26 (if there is no dispersion area 24). If there is a dispersion area 24, layer 22 and layer 26 may be connected via a mechanical means, such as, for example, a bracket, spacer, or any other method known in the art. Exterior armor subsystem 16 may be attached to vehicle hull 28 by any known technique in the art such as, for example, via mechanical fasteners. For example, exterior armor subsystem 16 may be bolted to hull 28.

[038] An average density of the low density material of intermediate layer 22 may be greater than an average density of the low density material of layer 20.
Additionally, an average density of layer 26 and hull 28 may be greater than the average density of the low density material of intermediate layer 22.

[039] It is contemplated that layer 20 and/or layer 22 may be oriented at an oblique angle relative to the expected trajectory. It is also contemplated that the layers of exterior armor subsystem 16 may increase in density in the direction of trajectory 12. This arrangement, which stacks low-density to high-density materials in the direction of trajectory 12, substantially reduces and slows a high-energy and high velocity jet of a hollow charge or other high energy projectile.

[040] Additionally, it is contemplated that an existing vehicle may be retrofitted with an exterior armor subsystem 16 and/or the alternative arrangements discussed below to gain the benefits described throughout by using an assemblage of required parts specific to the vehicle, e.g. in kit form, including, for example, appropriate fasteners for mounting.

[041] Fig 2 depicts an alternative arrangement of the layers depicted in Fig.
1. Specifically, Fig. 2 depicts an alternative arrangement including layers of differing thickness than the arrangement of Fig. 1.

[042] Fig. 3 depicts another alternative arrangement and number of layers.
As depicted in Fig. 3, exterior armor subsystem 16 includes a layer 20, a layer 22, and a second intermediate layer 30. Layer 30 may include materials similar to leading layer 20. In the embodiment depicted in Fig. 3, each of layers 20, 22, and 30 may be between 2" and 8" in thickness.

[043] Fig. 4 depicts another alternative arrangement of armor system 16 depicted in Fig. 3. As depicted in Fig. 4, a layer 31, of metal similar to layer 26, may be disposed between layer 26 and layer 30. Layer 22 may abut a rear surface of layer 20, layer 30 may abut a rear surface of layer 22, and layer 31 may abut a rear surface of layer 30. Further, an additional layer 27 of a glass fiber or composite material, may be disposed between layer 26 and hull 28. In the embodiment depicted in Fig 4, each of layers 22 and 20 may be between about 1"
and 6" in thickness, and each of layers 30, 31, 26, and 27 may be between about 1"
and 4" in thickness.

[044] As shown in Fig. 5, armor system 10 may be configured to protect vehicle interior 36 from projectiles. One or more panels 39 of exterior armor subsystem 16 may be provided and removably attached to vehicle 11. Panel 39 may be planar and may be removably attached to a side portion of vehicle 11. A
surface 41 of vehicle 11 may be configured to receive and bear flush against a surface 42 of a given panel 39. It is contemplated that panel 39 may be non-planar and include, for example, corners or curved portions. It is also contemplated that panel 39 may be removably attached to a top or bottom portion of vehicle 11.

[045] Fig. 6 illustrates another exemplary embodiment of the present inventions, namely armor system 110 for protecting a vehicle 111 (shown in Fig.
10) from projectiles. Armor system 110 may include a vehicle hull 128 and an exterior armor subsystem 116. Exterior armor subsystem 116 may include a leading sheet-like layer 120 that may be of a similar material as layer 20 of armor system 10. Exterior armor subsystem 116 may include a first dispersion area and a second dispersion area 132. Dispersion area 124 and dispersion area 132 may be similar to dispersion area 24 of armor system 10, and may each be between 1" and 6". Exterior armor subsystem 116 may also include an intermediate sheet-like layer 122 that may be similar material as layer 22 of armor system 10, and may be disposed between dispersion area 124 and dispersion area 132.

[046] As shown in Fig. 6, layer 122 may include a plurality of layers of material set at oblique angles relative to threat 12. Exterior armor subsystem may also include an intermediate layer 126 similar to layer 26 of armor system 10.
Hull 128 may be of a similar material as hull 28 of armor system 10. An additional layer of metal (not shown), similar to layer 126, may be disposed between hull and layer 126. Vehicle 111 may include any suitable interior armor system known in the art.

[047] Exterior armor subsystem 116 of Fig. 6 may be permanently mounted to hull 128, may be part of a modular system that may be easily removed from hull 128, or a portion of exterior armor subsystem 116 may be permanent and a portion may be modular. Layers 120, 122, and 126 may be attached to each other by any suitable method such as, for example, via adhesive having relatively high strength and relatively high elongation to break. For example, methacrylate adhesive, or any other suitable adhesive having high strength and high elongation to break, may be applied to the abutting surfaces to attach layers 120, 122, and 126 to each other. Adhesive may be applied to surfaces 120b and/or 122a to attach leading layer 120 to intermediate layer 122, and to surfaces 122b and/or 126a to attach intermediate layer 122 to intermediate layer 126 (if there is no dispersion area 124 and/or 132). If there is a dispersion area 124 and/or 132, layer 122 and layer may be connected via a mechanical means, such as, for example, a bracket, spacer, or any other method known in the art. Exterior armor subsystem 116 may be attached to vehicle hull 128 by any known technique in the art such as, for example, via mechanical fasteners. For example, exterior armor subsystem 116 may be bolted to hull 128.

[048] Fig 7 depicts an alternative arrangement of the layers depicted in Fig.
6. Specifically, Fig. 7 depicts an oblique leading layer 120 of exterior armor subsystem 116, followed by one or more oblique intermediate layers 122 and a perpendicular layer 122.

[049] Figure 8 depicts an alternative arrangement of layers. As depicted in Fig. 8, exterior armor subsystem 116 includes a leading layer 120, an intermediate layer 122, and a second intermediate layer 130. Layer 130 may include a material having a density greater than that of the materials of layers 120 and 122.
Each of layers 120 and 130 may be between 2" and 8" in thickness, layer 122 may have a combined thickness of between 2" and 8". Exterior armor subsystem 116 may include first dispersion area 124 and second dispersion area 132. As shown in Fig.
8, layer 122 may include a plurality of layers of material set at oblique angles relative to trajectory 12. Exterior armor subsystem 116 may also include an intermediate layer 126 similar to layer 26 of armor system 10. Hull 128 may be of a similar material as hull 28 of armor system 10. An additional layer of metal (not shown), similar to layer 126, may be disposed between hull 128 and layer 126.
Vehicle 111 may include any suitable interior armor system known in the art.

[050] Fig. 9 depicts another alternative arrangement of armor system 116 depicted in Fig. 8. As depicted in Fig. 9, a layer 131, of metal similar to layer 126, may be disposed between layer 126 and layer 130. Further, an additional layer 127 of a glass fiber or composite material, may be disposed between layer 126 and hull 128. In the embodiment depicted in Fig 9, each of layers 122 and 120 may be between about 1" and 6" in thickness, and each of layers 130, 131, 126, and may be between about 1" and 4" in thickness.

[051] As shown in Fig. 10, armor system 110 may be configured to protect vehicle interior 136 from projectiles. One or more panels 139 of exterior armor subsystem 116 may be provided and removably attached to vehicle 111. Panel 139 may be planar and may be removably attached to a side portion of vehicle 111.
A surface 141 of vehicle 111 may be configured to receive and bear flush against a surface 142 of a given panel 139. It is contemplated that panel 139 may be non-planar and include, for example, corners or curved portions. It is also contemplated that panel 139 may be removably attached to a top or bottom portion of vehicle 111.

[052] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed apparatus and method. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed method and apparatus. For example, one or more of the oblique-oriented layers in each of Figs. 6-9 could be positioned adjacent the hull. Also, multiple oblique-oriented layers could be interspersed with layers perpendicular to the threat direction or grouped or partially grouped together.
One skilled in the art, working with the present disclosure, would be able to construct a suitable armor system for a particular application. Thus, it is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

1. An armor system for protecting a vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull, the armor system comprising:
a modular armor subsystem configured to be mounted exterior to the vehicle hull, the modular armor subsystem including (a) a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory;
(b) a first intermediate sheet-like layer, the layer including low density material of a density less than metal, located between the leading layer and the hull;
(c) a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull; and (d) a dispersion area located between the first and the second intermediate sheet-like layers, wherein the density of the low density leading layer material is less than the density of the first intermediate layer low density material, and the density of the second intermediate layer material is greater than the density of the first intermediate layer low density material.

2. The armor system of claim 1, wherein the leading layer includes a low density material including one or more materials selected from polypropylene composite, reinforced polymer, reinforced plastic, a polyethylene composite, R-Glass composite in phenolic resin, S-Glass, E-Glass, and a woven blanket.

3. The armor system of claim 2, wherein the first intermediate sheet-like layer includes a low density plastic or rubber.

4. The armor system of claim 1, wherein the second intermediate sheet-like layer includes one of a low density material and a metal.

5. The armor system of claim 4, wherein the metal of the second intermediate sheet-like layer includes one or more metals selected from high strength aluminum, copper, steel, stainless steel, magnesium, molybdenum, copper, zirconium, titanium, and nickel.

6. The armor system of claim 4, wherein the low density material of the second intermediate sheet-like layer includes a low density composite material.

7. The armor system of claim 1, wherein the leading sheet-like layer includes a low density plastic or rubber.

8. The armor system of claim 7, wherein the first intermediate sheet-like layer includes a low density material having one or more materials selected from polypropylene composite, reinforced polymer, reinforced plastic, a polyethylene composite, R-Glass composite in phenolic resin, S-Glass, E-Glass, and a woven blanket.

9. The armor system of claim 1, further including a third intermediate sheet-like layer, the third intermediate sheet-like layer abutting a rear surface of the first intermediate sheet-like layer.

10. The armor system of claim 9, wherein the third intermediate sheet-like layer includes a low density material having one or more materials selected from polypropylene composite, reinforced polymer, reinforced plastic, a polyethylene composite, R-Glass composite in phenolic resin, S-Glass, E-Glass, and a woven blanket.

11. The armor system of claim 10, wherein the low density material includes a combination of materials selected from polypropylene composite, reinforced polymer, reinforced plastic, a polyethylene composite, R-Glass composite in phenolic resin, S-Glass, E-Glass, and a woven blanket.

12. The armor system of claim 9, wherein the thickness of each of the leading layer and the first, second, and third sheet-like intermediate layers is between about 2" and 8".

13. The armor system of claim 1, wherein the leading sheet-like layer and the first intermediate sheet-like layer are oriented at an oblique angle relative to the expected trajectory.

14. The armor system of claim 1, wherein the layers of the modular armor subsystem increase in density in the direction of the expected trajectory of the projectile.

15. An armor system for protecting a vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull, the armor system comprising:
a modular armor subsystem configured to be mounted exterior to the vehicle hull, the modular armor subsystem including (a) a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory;
(b) a first intermediate sheet-like layer, the layer including at least one sheet of low density material of a density less than metal, located between the leading layer and the hull;
(c) a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull; and (d) at least one dispersion area located between the first and the second intermediate sheet-like layers, wherein one of the leading sheet-like layer and the first intermediate sheet-like layer is oriented at an oblique angle relative to the expected trajectory, and the other of the leading sheet-like layer and the first intermediate sheet-like layer is oriented perpendicular relative to the expected trajectory.

16. The armor system of claim 15, wherein the leading layer includes one or more materials selected from polypropylene composite, reinforced polymer, reinforced plastic, a polyethylene composite, R-Glass composite in phenolic resin, S-Glass, E-Glass, and a woven blanket.

17. The armor system of claim 16, wherein the first intermediate sheet-like layer includes a low density plastic or rubber.

18. The armor system of claim 17, wherein the first intermediate sheet-like layer has a thickness of between about 1" and about 8".

19. The armor system of claim 16, wherein the leading layer has a thickness of between about 6" and about 14".

20. An armor system for protecting a vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull, the armor system comprising:
a modular armor subsystem configured to be mounted exterior to the vehicle hull, the modular armor subsystem including (a) a leading sheet-like layer, the layer including a low density material of a density less than metal; and (b) a first intermediate sheet-like layer, the layer including at least one sheet of low density material of a density less than metal, located between the leading layer and the hull (c) a second intermediate sheet-like layer, located between the first intermediate sheet-like layer and the hull and positioned generally perpendicular to the expected trajectory; and (d) wherein one of the leading sheet-like layer and the first intermediate sheet-like layer is oriented at an oblique angle relative to the expected trajectory, and the other of the leading sheet-like layer and the first intermediate sheet-like layer is oriented perpendicular relative to the expected trajectory.

21. The armor system of claim 20, further including a third sheet-like layer, the layer including low density material of a density less than metal and located between the first intermediate layer and the second intermediate layer.

22. The armor system of claim 20, further including at least one dispersion area located between the leading sheet-like layer and the second intermediate sheet-like layer.

23. The armor system of claim 22, wherein the at least one dispersion area includes two dispersion areas, the first dispersion area located between the leading layer and the first intermediate layer, and the second dispersion area located between the first intermediate layer and the second intermediate layer.

24. The armor system of claim 20, wherein the at least one sheet of the first intermediate sheet-like layer is three sheets, and wherein each sheet is spaced apart.

25. The armor system of claim 24, wherein the combined thickness of the three sheets is between about 2" to about 8".

26. A method for configuring an armor system to protect a vehicle interior from differing types of projectiles each having an expected trajectory, the vehicle having a permanent armor subsystem including a sheet-like layer having metal and having an outer surface, the method comprising:
providing a modular armor subsystem including one or more panels each having (a) a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory;
(b) a first intermediate sheet-like layer, the layer including low density material of a density less than metal, located between the leading layer and a second intermediate sheet-like layer;
(c) a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull;
(d) a dispersion area located between the first and the second intermediate sheet-like layers; and removably attaching the modular armor subsystem adjacent to the outer surface of the sheet-like metal layer of the permanent armor subsystem.

27. The method of claim 26, wherein providing the modular armor subsystem includes applying adhesive to the surfaces of the layers of the modular armor subsystem.

28. The method of claim 26, wherein the outer surface of the sheet-like layer having metal of the permanent armor subsystem is configured to bear flush against an outer surface of the second intermediate sheet-like layer of the modular armor subsystem.

29. A method for configuring an armor system to protect a vehicle interior from differing types of projectiles each having an expected trajectory, the vehicle having a permanent armor subsystem including a sheet-like layer having metal and having an outer surface, the method comprising:
providing a modular armor subsystem including one or more panels each having (a) a leading sheet-like layer, the layer including a low density material of a density less than metal; and (b) a first intermediate sheet-like layer, the layer including at least one sheet of low density material of a density less than metal, located between the leading layer and the hull (c) the second intermediate sheet-like layer, located between the first intermediate sheet-like layer and the hull and positioned generally perpendicular to the expected trajectory; and (d) wherein one of the leading sheet-like layer and the first intermediate sheet-like layer is oriented at an oblique angle relative to the expected trajectory, and the other of the leading sheet-like layer and the first intermediate sheet-like layer is oriented perpendicular relative to the expected trajectory; and removably attaching the modular armor subsystem adjacent to the outer surface of the sheet-like metal layer of the permanent armor subsystem.

30. A kit for retrofitting a vehicle with an exterior armor subsystem to protect the vehicle from a projectile, the projectile having an expected trajectory and the vehicle having a hull, the kit comprising:
a modular armor subsystem configured to be mounted exterior to the vehicle hull, the modular armor subsystem including (a) a leading sheet-like layer, the layer including a low density material of a density less than metal, and leading relative to the expected projectile trajectory;
(b) a first intermediate sheet-like layer, the layer including low density material of a density less than metal, located between the leading layer and the hull;
(c) a second intermediate sheet-like layer, the layer located between the first intermediate sheet-like layer and the hull; and (d) a dispersion area located between the first and the second intermediate sheet-like layers, wherein the density of the low density leading layer material is less than the density of the first intermediate layer low density material, and the density of the second intermediate layer material is greater than the density of the first intermediate layer low density material.