U.S. patent application number 11/971475 was filed with the patent office on 2010-11-11 for armor protection against explosively-formed projectiles.
This patent application is currently assigned to INTELLECTUAL PROPERTY HOLDINGS, LLC. Invention is credited to Jeff Lennartz, Dan T. Moore, III, Matthew T. Mullarkey, Mark Russell, Ajit Y. Sane, Samuel Robert Skaggs.
Application Number | 20100282062 11/971475 |
Document ID | / |
Family ID | 43061567 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100282062 |
Kind Code |
A1 |
Sane; Ajit Y. ; et
al. |
November 11, 2010 |
ARMOR PROTECTION AGAINST EXPLOSIVELY-FORMED PROJECTILES
Abstract
A hybrid armor architecture is provided that is effective
against explosively-formed and other high-energy ballistic
projectiles. The architecture includes at least one laminate
reactive armor panel including a layer of non-explosively reactive
material sandwiched between outer layers of a ductile material, an
armor plate disposed behind the laminate reactive armor panel, and
a flyer plate disposed behind the armor plate. The flyer plate or a
portion thereof is configured to move toward and impact a body
panel that is being protected 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.
Inventors: |
Sane; Ajit Y.; (Medina,
OH) ; Mullarkey; Matthew T.; (Bay Village, OH)
; Skaggs; Samuel Robert; (Santa Fe, NM) ;
Lennartz; Jeff; (Cleveland, OH) ; Moore, III; Dan
T.; (Cleveland Heights, OH) ; Russell; Mark;
(Cleveland, OH) |
Correspondence
Address: |
Pearne & Gordon LLP
1801 East 9th Street, Suite 1200
Cleveland
OH
44114-3108
US
|
Assignee: |
INTELLECTUAL PROPERTY HOLDINGS,
LLC
Cleveland
OH
|
Family ID: |
43061567 |
Appl. No.: |
11/971475 |
Filed: |
January 9, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60988468 |
Nov 16, 2007 |
|
|
|
61004853 |
Nov 30, 2007 |
|
|
|
Current U.S.
Class: |
89/36.02 ;
89/902; 89/912; 89/937 |
Current CPC
Class: |
F41H 5/013 20130101;
F41H 5/023 20130101; F41H 5/007 20130101; F41H 5/0442 20130101;
F41H 5/0457 20130101 |
Class at
Publication: |
89/36.02 ;
89/902; 89/912; 89/937 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
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.
Description
[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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