U.S. patent application number 14/212386 was filed with the patent office on 2015-09-10 for polymer and block copolymer, ceramic composite armor system.
The applicant listed for this patent is Phoenix Armor, LLC. Invention is credited to Murray L. Neal.
Application Number | 20150253114 14/212386 |
Document ID | / |
Family ID | 52022892 |
Filed Date | 2015-09-10 |
United States Patent
Application |
20150253114 |
Kind Code |
A1 |
Neal; Murray L. |
September 10, 2015 |
POLYMER AND BLOCK COPOLYMER, CERAMIC COMPOSITE ARMOR SYSTEM
Abstract
Modern military operations, technology-driven war tactics and
techniques, and availability of newly developed, current and
surplus military ammunition necessitate the development of advanced
ballistic protection for body armor, vehicle, vessel and aircraft
systems that are damage-resistant, flexible, lightweight, capable
of defeating multiple threats, while providing substantial energy
absorbing capacity. A number of studies related to new technology
concepts and designs of body armor materials (including those
derived from or inspired by nature) have been conducted in the last
decade to forge an attempt at meeting such demands. Ballistic
textiles, ceramics, and laminated composites are among the leading
materials used in modern body armor designs, and nano-particle and
natural fiber filled composites are candidate materials for
new-generation armor systems. Properties and ballistic resistance
mechanisms of such materials have been extensively investigated,
however, polymeric improvements have had limited scope and
ceramic/polymer structured architectures have not been explored.
The combination of these materials in an armor composite system
with the high impact properties of ceramics and the extreme
viscoelastic properties of polymers, would out-perform any of
today's current lightweight rigidized polymeric systems, while
maintaining superior lightweight ballistic and fragmentation
performance capabilities as compared to the latest state-of-the-art
lightweight ceramic glass and/or textile resin composite
systems.
Inventors: |
Neal; Murray L.; (Missoula,
MT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Phoenix Armor, LLC |
Scottsdale |
AZ |
US |
|
|
Family ID: |
52022892 |
Appl. No.: |
14/212386 |
Filed: |
March 14, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61784872 |
Mar 14, 2013 |
|
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|
Current U.S.
Class: |
89/36.02 |
Current CPC
Class: |
F41H 5/0421 20130101;
F41H 5/0428 20130101; F41H 5/0457 20130101; F41H 5/0492
20130101 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
1. An apparatus for use in an armor system comprising: a plurality
of discs or tiles, each of the plurality of discs or tiles having a
strike face and a non-strike face connected by lateral sides; and a
polymeric body wrap coupled to the non-strike face of each of the
plurality of discs or tiles.
2. The apparatus of claim 1 wherein each of the plurality of discs
or tiles comprise a ceramic material.
3. The apparatus of claim 1 wherein each of the plurality of discs
or tiles comprise a polymeric material.
4. The apparatus of claim 1 wherein each of the plurality of discs
or tiles comprise a ceramic and a polymer composite material.
5. The apparatus of claim 1 wherein each of the plurality of discs
are discus shaped discs.
6. The apparatus of claim 1 wherein at least one of the strike face
or the non-strike face is a non-planar surface.
7. The apparatus of claim 1 wherein at least one face of the
plurality of discs or tiles is planar.
8. The apparatus of claim 1 further comprising: a glass fiber wrap
coupled to the strike face of each of the discs or tiles.
9. The apparatus of claim 7 wherein the polymeric body wrap is
coupled to only the non-strike face and the lateral sides of each
of the discs or tiles and the glass fiber wrap is coupled to only
the strike face.
10. The apparatus of claim 7 wherein the glass fiber wrap
completely encases the discs or tiles and the polymeric body wrap
is wrapped only around portions of the glass fiber wrap covering
the non-strike face and the lateral sides.
11. The apparatus of claim 7 wherein the glass fiber wrap
completely encases the discs or tiles and the polymeric body wrap
completely encases the glass fiber wrap.
12. The apparatus of claim 1 further comprising: a titanium
encasement wrap coupled to the polymeric containment wrap.
13. The apparatus of claim 2 wherein the ceramic material is
selected from the group consisting of aluminum oxide, silicon
carbide, silicon nitride, boron carbide and titanium diboride.
14. The apparatus of claim 1 wherein the polymeric body wrap is a
matrix-reinforced polymeric composite material.
15. An apparatus for use in an armor system comprising: a plurality
of discs or tiles comprising a polymer composite material; and a
containment wrap coupled to each of the plurality of discs or
tiles.
16. The apparatus of claim 15 wherein the polymer composite
material is a ceramic and polymer bonded material.
17. The apparatus of claim 15 wherein the containment wrap
comprises a titanium material completely encasing each of the
plurality of discs or tiles.
18. A body armor comprising: a plurality of discs or tiles; a
plurality of polymeric body wraps, each wrap at least partially
encasing one of the discs or tiles; and a substrate coupled to the
encased discs or tiles to retain the discs or tiles in a fixed
pattern.
19. The apparatus of claim 18 wherein each of the plurality of
discs or tiles comprise a ceramic material.
20. The apparatus of claim 18 wherein each of the plurality of
discs or tiles comprise a polymeric material.
21. The apparatus of claim 18 wherein each of the plurality of
discs or tiles comprise a ceramic and a polymer composite
material.
22. The apparatus of claim 18 wherein each of the plurality of
discs are discus shaped discs.
23. The apparatus of claim 18 wherein at least one face of the
discs or tiles is a non-planar surface.
24. The apparatus of claim 18 wherein at least one face of the
plurality of discs or tiles is planar.
25. The apparatus of claim 18 further comprising: a glass fiber
wrap coupled to a face of each of the discs or tiles.
26. The apparatus of claim 25 wherein the polymeric body wrap is
coupled to only a non-strike face and lateral sides of each of the
discs or tiles and the glass fiber wrap is coupled to only a strike
face.
27. The apparatus of claim 25 wherein the glass fiber wrap
completely encases the discs or tiles and the polymeric body wrap
is wrapped only around portions of the glass fiber wrap covering a
non-strike face and lateral sides of the discs or tiles.
28. The apparatus of claim 25 wherein the glass fiber wrap
completely encases the discs or tiles and the polymeric body wrap
completely encases the glass fiber wrap.
29. The apparatus of claim 18 further comprising: a titanium
encasement wrap coupled to the polymeric containment wrap.
30. The apparatus of claim 19 wherein the ceramic material is
selected from the group consisting of aluminum oxide, silicon
carbide, silicon nitride, boron carbide and titanium diboride.
31. The apparatus of claim 18 wherein the polymeric body wrap is a
matrix-reinforced polymeric composite material.
32. The apparatus of claim 18 wherein the fixed pattern is an
imbricated pattern.
33. The apparatus of claim 18 wherein the fixed pattern is a mosaic
pattern in which the discs or tiles are laid out in a side-by-side
pattern.
34. A method of making a body armor comprising: providing a
plurality of discs or tiles, wherein each of the discs or tiles are
either encased within a polymeric containment wrap or formed by a
polymeric material; laying out the plurality of discs or tiles in a
fixed pattern on a substrate; and adhering the substrate to a first
side of the discs or tiles.
35. The method of claim 34 wherein the fixed pattern is an
imbricated pattern comprising overlapping each disc or tile upon a
successive disc or tile so that each disc or tile tilts from a
horizontal plane defined by the substrate.
36. The method of claim 34 wherein the fixed pattern is a mosaic
pattern comprising each disc or tile arranged in a side by side
configuration.
37. An apparatus for use in an armor system comprising: a plurality
of discs or tiles, each of the plurality of discs or tiles having a
strike face and a non-strike face connected by lateral sides; and a
body wrap coupled to the non-strike face of each of the plurality
of discs or tiles.
38. The apparatus of claim 37 wherein the plurality of discs or
tiles comprise one of a functionally graded material (FGM) and
polymeric construction, cermet and polymeric construction,
encapsulated ceramic-polymeric construction, encapsulated
ceramic-polymeric-metal construction, encapsulated polymeric
construction, solid polymeric composite, a solid polymeric ceramic
induced constituent composite, a nano-ceramic or a nano-composite
with matrices and filler materials.
39. The apparatus of claim 37 wherein the body wrap comprises a
textile wrap material selected from the group consisting of
aramids, para-aramids, carbon fiber, glass fiber, polyethylene
fabrics carbon fibers, woven stainless steel textile, woven
non-magnetic nitinol textile, E-Glass, S2 glass, and nano-infused
aramid.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a non-provisional patent application
that claims the benefit of the filing date of, and priority to,
U.S. Provisional Application No. 61/784,872, filed Mar. 14, 2013,
the entirety of which is incorporated herein by reference.
FIELD
[0002] The invention relates to protective armor systems. More
specifically, the invention relates to armoring systems suitable
for body armor; and armoring vehicles, vessels, and aircraft,
designed from polymer and block copolymer composite ceramic armor
technologies.
BACKGROUND
[0003] There has been and the need will always be there for reduced
weight for rifle, heavy machine gun (HMG), and 20 mm to 30 mm
cannon threat defeating ballistic and fragmentation resistant armor
products, utilized in body armor and light weight rigid armor
applications for vehicles, vessels and aircraft applications, while
increasing the ballistic and fragmentation performance threat
defeating terminal impact capabilities of the specific components
and ultimately complete composite armor systems.
[0004] Several additional material substrate compositions have been
identified in this invention that have a substantial potential for
weight reductions of such ballistic and fragmentation resistant
defeating armor systems, while maintaining other physical and
mechanical performance enhanced attributes and increased
capabilities.
[0005] However, one of the most promising, and currently within
technological reach is the utilization of polymeric compositions
used in combination with ceramics and/or titanium for reduced
weight without the sacrifice of rifle, HMG and 20 mm to 30 mm
cannon defeating ballistic performance capabilities, and the
secondary fragmentation and shrapnel resistance performance
capabilities. The most severe threats being the multi-purpose high
explosive (HE) HMG and 20 mm to 30 mm cannon projectiles which
detonate upon impact.
[0006] The ability to have such a defeat capable armor technology
system, with a reduced areal density below the current
state-of-the-art systems, while gaining specific ballistic and/or
fragmentation resistant performance capabilities, is paramount. The
past has shown that in order to achieve reduced weight in an armor
system there has always been a need to either reduce the
performance capabilities of that armor system and/or the amount of
protective armor fielded. That dilemma has now been surmounted.
[0007] A composite armor solution is a complex armor system
comprised of several, uniquely different materials configured into
a specific architecture, which forms a non-homogeneous single
source armor material. This hybridized combining of multiple
constituent materials can often have the physical and mechanical
attributes of a homogeneous system or act uniquely different with
attributes not fully sustainable in a homogeneous armor system. A
truly refined and optimized composite system can be "tuned" to meet
multiple threat resistance performance capabilities. More than a
fundamental requisite understanding of material science such as the
physical and mechanical properties, and the finite analysis of each
constituent material, is necessary to link the specific material
properties to the actual behavior of the materials independently or
as an entire system is required.
[0008] Most armor systems are not well designed in that they are
generally constructed then tested, then modified and tested again,
often numerous times until some acceptable result is acquired. This
does not provide any understanding to the constituent materials,
let alone a composite system and the interactive attributes either
positive or negative and their cumulative performance capabilities,
let alone any "tunable attributes", given that composite armors are
rate dependent constructions with often varied architectures,
adhesion, cohesion bonding influences, constituent glass transition
phases, and mechanical impedance coupled with extensional wave
transfers.
[0009] A current typical ceramic composite armor system for the use
in body armor and transport armor applications providing protection
from small arms threats to HMG threats, predominantly include a
ceramic component backed by a fiber reinforced polymer matrix
composite component, or an all aramid, polyethylene or combined
textile composite (hybrid) polymer matrix textile backing
component.
[0010] The system that surmounts these is the (Dragon Skin.RTM.)
armor technology system. This technology has been seen as the
forerunner in what is defined as a scaled lamellar design often
referred to as the first biologically inspired modern armor
technology.
[0011] This technology has provided the following eleven enhanced
physical and mechanical attributes and increased capabilities not
associated with any currently manufactured and deployed armor
systems. These attributes are listed as currently employed in a
flexible rifle defeating body armor system, but with the exception
of flexibility in varied applications, these attributes also lend
themselves to vehicle, vessel and aircraft rigidized applications.
Additionally, these attributes have been substantiated by the U.S.
Army Research Laboratories (ARL) and the Defense Science Testing
Laboratory in the United Kingdom (DSTL).
[0012] 1. Weighs Less
[0013] The Dragon Skin.RTM. technology's flexible rifle defeating
body armor has the lightest weight for the ballistic and
fragmentation protection capabilities provided. No other technology
has the protection (coverage and impact capabilities) that the
Dragon Skin.RTM. technology provides. Less Weight=Greater
comfort+Increased Mobility=Increased Soldier Survivability.
[0014] 2. Increased Multiple Repeat Hit Capability
[0015] The Dragon Skin.RTM. technology can sustain greater amounts
of impacts than current monolithic ceramic plate technologies
affording increased soldier survivability. Increased Hit
Capability=Longer or Multiple Mission Soldier Survivability.
[0016] 3. Less Trauma (Backface Signature)
[0017] The Dragon Skin.RTM. technology has demonstrated 52-64%
reduction in average back face deformation/signature (reduced
trauma to the body). This means the wearer can take multiple hits
on the vest and keep fighting effectively. This aspect, by itself,
is incredibly important, especially in urban warfare and CQB (Close
Quarters Battle) scenarios. Less Trauma=Soldier Mission
Sustainability.
[0018] 4. Increased Flexibility
[0019] The Dragon Skin.RTM. technology has flexible mobility. This
flexible mobility increases the comfort and mobility of the wearer.
The flexible configuration of the imbricated discs architecture
provides the flexibility to bend this technology in all directions,
and to twist the armor in opposing directions, thereby, allowing
the wearer to move with greater ease decreasing the level of energy
required to move. Less Energy+Greater Comfort=Less BTU's=Cooler
Soldier.
[0020] 5. Increased Durability
[0021] The Dragon Skin.RTM. technology has a substantial increase
in durability as compared to the monolithic ceramic plate
technology. Less Subject to Damage=Longer Service Life=Less Life
Cycle Costs.
[0022] 6. Edge Hit Capability
[0023] The Dragon Skin.RTM. technology has demonstrated reduced
edge affected zone increasing effective area of coverage provided
by the ceramic discs. Increased edge hit capability=increased
protection.
[0024] 7. Greater Coverage
[0025] The Dragon Skin.RTM. technology offers vastly greater
amounts of coverage options. It is the first body armor system that
can be tailored to be mission specific, up to covering the entire
torso. This is especially needed in a heavily IED or VBIED laden
battlefield. Greater Coverage=Increased Soldier Survivability.
[0026] 8. Reduced Ricochet Threat
[0027] The Dragon Skin.RTM. technology has shown to eliminate
ricochets from obliquity/angled shots up to 60.degree.. The rigid
plates have ricochet shots starting at approximately
32.degree.-35.degree.. This too increases soldier survivability by
reducing the probability of one soldier being shot and the
projectile ricocheting off him and into the next soldier injuring
or fatally wounding him/her. Reduced Ricochet=Less Collateral
Injuries.
[0028] 9. Fit Flexibility
[0029] The Dragon Skin.RTM. technology is tailor-able for both male
and females to the 97 percentile. It can be used not only in a
tactical configuration but also in concealed variants for both
genders. Greater Tailor-ability=More Soldiers Provided Adequate
Armor Protection.
[0030] 10. Increased Projectile Diversity
[0031] The Dragon Skin.RTM. technology defeats the compendium of
projectile threats faced world-wide as threats to the military, not
just regional threats per engagement. The military is deployed
world-wide and so too should their armor have the ability to defeat
all known projectiles within a specific threat category in both
current and past conflict circulation, at and above muzzle
velocity, not just a select few threats based on a single area of
operation. Increased Projectile Diversity=Less Costs for Multiple
Threat Resistant Systems=Fewer Dollars Spent.
[0032] 11. Eliminate Ballistic Shatter-Gap Phenomenon
[0033] The Dragon Skin.RTM. technology due to its architecture and
configurational design, eliminates the shatter-gap ballistic
failure phenomenon exhibited in monolithic tile and plate ceramic
armor composites. The elimination of ballistic failure mechanisms
inherent in these types of armor composites, bridges a substantial
life threatening capability hole in current ceramic body armor
composite systems. Increased physical and mechanical material
properties=increased Soldier Survivability.
SUMMARY
[0034] An armoring system for body armor; and armoring vehicles,
vessels, and aircraft. A composite armoring architecture consisting
of a plurality of discus-shaped discs or tiles with or without a
flat planular surface or surfaces, which are individually wrapped
in a textile and/or titanium containment wrap and encased within a
polymeric substrate; or solely encased within a polymeric
substrate; or comprised as a constituent component within a solid
polymeric substrate, or encased within a titanium exterior wrap.
These polymeric substrates are to have exceptionally high impact
properties that absorb energy when subjected to high stress impact
induced compressive shock loading before fracture, thereby
increasing tensile elongation through its physical viscoelastic
properties. Then such architectures are either laid out in a mosaic
side-by-side single or multiple row pattern; or an imbricated
pattern row by row such that each disc in a row is in substantially
a straight line with other discs in the row and overlaps a segment
of a disc in an adjacent row. The mosaic or imbricated pattern is
then adhered to a flexible high tensile strength substrate and
overlaid by a second high tensile strength layer such that the
mosaic or imbricated pattern is enveloped between the substrate and
the second layer. A second embodiment arranges the mosaic
juxtaposed in a side-by-side pattern into a polymeric configuration
that encapsulates the entire mosaic tiled arrangement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The embodiments disclosed herein are illustrated by way of
example and not by way of limitation in the figures of the
accompanying drawings in which like references indicate similar
elements. It should be noted that references to "an" or "one"
embodiment in this disclosure are not necessarily to the same
embodiment, and they mean at least one.
[0036] FIG. 1 illustrates the encapsulation of a ceramic core with
a titanium FGM shell.
[0037] FIG. 2 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0038] FIG. 3 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0039] FIG. 4 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0040] FIG. 5 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0041] FIG. 6 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0042] FIG. 7 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0043] FIG. 8 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0044] FIG. 9 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0045] FIG. 10 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0046] FIG. 11 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0047] FIG. 12 illustrates a cross-sectional side view of one
embodiment of a composite disc.
[0048] FIG. 13 is a perspective view of one embodiment of a
non-flat planar disc.
[0049] FIG. 14 shows a side view of another embodiment of a flat
planar disc or tile.
[0050] FIG. 15 is a perspective view of a disc of an alternative
embodiment of the invention.
[0051] FIG. 16 is a side view of the alternative embodiment shown
in FIG. 15.
[0052] FIGS. 17A-17C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0053] FIGS. 18A-18C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0054] FIGS. 19A-19C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0055] FIGS. 20A-20C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0056] FIGS. 21A-21C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0057] FIGS. 22A-22C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0058] FIGS. 23A-23C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0059] FIGS. 24A-24C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0060] FIGS. 25A-25C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0061] FIGS. 26A-26C illustrate one embodiment of a tile that may
be used according to the instant invention.
[0062] FIG. 27 shows an imbricated pattern of discs coupled to a
substrate.
[0063] FIG. 28 is a frontal view of one embodiment of a body armor
vest within which discs or tiles may be integrated.
[0064] FIG. 29 is a cutaway frontal view of one embodiment of a
suit of body armor.
[0065] FIG. 30 illustrates one embodiment of a mosaic tile
pattern.
[0066] FIG. 31 illustrates one embodiment of an imbricated tile
pattern.
[0067] FIG. 32 illustrates one embodiment of an imbricated disc
pattern.
[0068] FIG. 33 illustrates one embodiment of an imbricated tile
pattern.
[0069] FIG. 34 illustrates one embodiment of an imbricated tile
pattern.
[0070] FIG. 35 illustrates one embodiment of an imbricated tile
pattern.
[0071] FIG. 36 illustrates a perspective view of one embodiment of
a tile.
[0072] FIG. 37 illustrates a top plan view of one embodiment of a
tile.
[0073] FIG. 38 illustrates one embodiment of an imbricated tile
pattern.
[0074] FIG. 39 illustrates one embodiment of an imbricated tile
pattern.
DETAILED DESCRIPTION
[0075] In this section we shall explain several preferred
embodiments with reference to the appended drawings. Whenever the
shapes, relative positions and other aspects of the parts described
in the embodiments are not clearly defined, the scope of the
embodiments is not limited only to the parts shown, which are meant
merely for the purpose of illustration. Also, while numerous
details are set forth, it is understood that some embodiments may
be practiced without these details. In other instances, well-known
structures and techniques have not been shown in detail so as not
to obscure the understanding of this description.
[0076] Several specific processes occur during the terminal
ballistic event/impact of such a rifle, heavy machine gun and 20 mm
to 30 mm cannon defeating threat armor systems:
[0077] 1. The projectile impacts the strike face of the armor
system imparting its kinetic energy onto and through the surface of
the armor system.
[0078] 2. A shock wave (extensional shock wave transfer) is
generated through each of the two primary component mediums; in the
ceramic strike face and through the balance of the composite
component behind the ceramics, the shock wave creates compressive,
tensile and shear stresses.
[0079] 3. These stresses in the ceramic component, usually create a
circumferential (cone shape "conoidal shaped area") crush zone with
radial tensile fracturing cracks propagating outward from the
epicenter of the impacting projectile. The size of the crush zone,
combined with the quantity, depth, and widths of these tensile
stress propagated cracks are dependent upon the shape and
configurational design of the strike face component.
[0080] 4. The ceramic will impart a specific amount of stress
directly upon the projectile. The type and amount of stress is
dependent upon the shape and configurational design of the strike
face component. The greater the dwell time or the time that the
projectile resides upon the surface of the armor before it breaches
the surface, the greater the type and amount of imparted stresses
there will be on the projectile.
[0081] 5. The projectile is deformed, shattered and/or eroded,
thereby dumping mass and reducing the amount of further energy
transfer into the armor system.
[0082] 6. The projectile and or its fragments may continue to
penetrate through the ceramic component of the composite armor
system.
[0083] 7. The projectile or fragments of both the projectile and
the ceramic component may enter into the composite backing directly
behind the ceramic and are stopped within it.
[0084] 8. Projectile impact and momentum energy is transferred
through the armor resulting in a rearward deformation or bulge of
the rear surface of the armor, created in the process of energy
accumulated through the various armor system projectile defeat
mechanisms. This bulge or deformation is often referred to as
either "Behind Armor Blunt Trauma", "Backface Signature" (BFS) or
"Backface Deformation" (BFD), and will either stay deformed in a
rearward parabolic shape in the case of a matrix composite or will
stay pliable and slightly return back towards its original shape in
the case of a flexible textile only backing. The latter is more
preferable due to a wearer's perspective utilizing body armor, as
it will not maintain that rearward bulge into the body subsequent
to the impact. This rearward bulge if rigid can further cause
irritation of the bruised area of the torso, if required to be worn
for protection subsequent to impact. In vehicle, vessel and
aircraft applications, appropriately selected matrix materials
inducing rigidity will preclude obstructing or damaging mechanical,
electrical, or hydraulic mechanisms, wires, or fluid transport
lines.
[0085] Based upon the varied projectile design parameters, it is
necessary to understand the specific criteria behind the design of
projectiles whose sole purpose is the defeat of armor systems,
these would be considered armor piercing projectiles. There are
four (4) primary armor piercing projectile design constraints that
attribute to the defeat of an armor. These are the projectiles
velocity, the density or weight of the projectile material(s), the
design geometry of the projectile, and the strength of the
projectile material composition.
[0086] There is a descending order of importance of these
projectile design attributes, though, and their importance on armor
defeat. These are based solely on overmatch proficiencies of the
projectile. The first most important aspect would be the material
strength which is the parameter that permits the projectile to
maintain the designed armor piercing shape during the penetration
process. Then, the geometry takes the forefront, which represents
the aspect ratio of the projectile and the meplat and ogive regions
of the projectile. The first two are important until the armor
material to be defeated matches or is stronger than the strength
and geometry of the projectile. At that point the last two
attributes step up, velocity and density. Velocity generally can
overmatch an armor system provided that there is sufficient mass to
aid in imparting kinetic energy displacement into the armor
material to be penetrated. Exothermic heat transfer produced by the
projectiles impact also aids substantially in the armor systems
mechanical failure due to entropy.
[0087] Concepts--There are at least seven different synthesized
manufacturing and processing concepts/embodiments that do work for
the hybridized composite armor component as described in this
invention. These resultant designs will provide for a lighter
weight composite armor system that will maintain the superior
proven performance capabilities of the Dragon Skin.RTM. technology
armor system or other tile/plate technologies through the use of
synthesized polymeric reinforcement to reduce the amount of ceramic
and/or textile backing materials required to defeat the threats.
The resultant armor design and composite configurations will be
lighter in weight.
[0088] These are: Functionally graded material (FGM) and polymeric
construction; Cermet and polymeric construction; Encapsulated
ceramic-polymeric construction; Encapsulated
ceramic-polymeric-metal construction; Encapsulated polymeric
construction; Solid polymeric composite, solid polymeric ceramic
induced constituent composite.
[0089] Functionally graded material (FGM) composite compositions
consist of microstructurally engineered gradual transitions in
microstructures and/or compositions of two or more materials. The
material compositions and material properties transition gradually,
rather than abruptly, from one end-phase material to another
end-phase material. Therefore, there is a gradual, rather than
abrupt interface between the two end surfaces of each material.
[0090] The foundation of the FGM is the graded porosity ceramic
strike face, which is fully densified with little or no
substantiated open porosity on the strike face and then gradually
changing into an open porosity surface on the rear face of the
ceramic. Polymers or metals are then infiltrated into the porous
side of the ceramic disc to provide a lightweight energy absorbing
backing material.
[0091] The finished tile or disc will consist of a very hard, dense
and fracture tough ceramic strike face that will initiate the
destruction of the projectile upon impact, and then provide a
gradual transition to the tough ductile polymer and/or metal
material that finalizes the energy absorption and fragment
retention of the projectile jacket and core compositions through
the encapsulating containment process. This too aids in attenuating
and absorbing the resultant energy, extensional shock wave
propagation transfer, and resultant backface deformation of the
armor system.
[0092] This gradual method of providing a transitional interface
also aids in the preclusion of extensional shock wave transfer
collision between the outbound and inbound paths at the two
dissimilar material boundaries. This is crucial in providing an
armor system that has sustainable survivability from multiple
repeat impacts, and precludes additional tensile stress fracturing
of the ceramic component.
[0093] The final added benefit would be the built-in frontal,
rearward and lateral constraint which would enhance in retarding
and containment of the ceramic dilatancy as illustrated in FIG.
1.
[0094] FIG. 1 shows the encapsulation of a ceramic core with a
titanium shell. This design can be conducted through a modified FGM
process, cermet process or an adhesive applied and welded
application.
[0095] A cermet is a composite material composed of ceramic (cer)
and metallic (met) materials. A cermet is ideally designed to have
the optimal properties of both a ceramic, such as high temperature
resistance and hardness, and those of a metal, such as the ability
to undergo plastic deformation. The metal is used as a binder for
an oxide, boride, or carbide. Generally, the metallic elements used
are nickel, molybdenum, and cobalt. Depending on the physical
structure of the material, cermets can also be metal matrix
composites, but cermets are usually less than 20% metal by
volume.
[0096] Ceramic/Polymer bonded composition, & solid polymer
composition. This does offer the best of a polymer technology
combined with the attributes of ceramics. This is currently in the
compositional optimization process with the ceramic disc
configurations of one embodiment. Various reinforced disc
configurations are illustrated in FIGS. 2-12.
[0097] NOTE: The drawings provided herein are not to scale, and are
for visual representations of constituent component configurations
for the disc shaped ceramics of one embodiment of this
invention.
[0098] FIG. 2 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc with an
E-glass wrap on the strike face of the ceramic disc and a polymer
body wrap from the lateral sides through to the rear containment in
a single unitized configuration.
[0099] FIG. 3 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc with an
E-glass wrap on the front, rear and sides of the ceramic and a
polymer body wrap from the lateral sides through to the rear
containment in a single unitized configuration.
[0100] FIG. 4 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc without an
E-glass wrap on the ceramic disc and a complete polymer body
encasement.
[0101] FIG. 5 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc with an
E-glass wrap on the front, rear and sides of the ceramic disc and a
complete polymer body encasement.
[0102] FIG. 6 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc with an
E-glass wrap on the front, rear and sides of the ceramic disc and a
polymer body wrap with a titanium encasement.
[0103] FIG. 7 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc without an
E-glass wrap on the ceramic disc and a complete polymer body
surround with a titanium encasement.
[0104] FIG. 8 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a ceramic disc with an
E-glass wrap on the front, rear and sides of the ceramic disc and a
complete polymer body surround with a titanium encasement.
[0105] FIG. 9 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a solid polymer disc with a
titanium encasement on the front, rear and sides of the polymer
disc.
[0106] FIG. 10 illustrates a cross-sectional side view of one
embodiment of a composite disc. This is a solid polymer disc
without any encasement on the front, rear and sides of the polymer
disc.
[0107] FIG. 11 illustrates a cross-sectional side view of one
embodiment of a composite disc. The disc of FIG. 11 is a composite
disc made of a ceramic and a polymeric material without any
encasement.
[0108] FIG. 12 illustrates a cross-sectional side view of one
embodiment of a composite disc. The disc of FIG. 12 is a composite
disc made of a ceramic and a polymeric material with a titanium
encasement on the front, rear and sides of the disc.
[0109] Ceramic Substrate Attributes
[0110] Fracture at high strain rates is another seriously important
consideration in armor penetrator and armor performance
capabilities. Although fracture is generally detrimental to armor
penetrators, certain types of armor may, in fact, turn a fracture
event into an advantage.
[0111] For example, ceramic armors can be designed into a system
that will provide for an allowance of fracturing through controlled
dilatancy, i.e., the ceramic's tendency to readily expand into any
free volume when fractured. A critical factor in this process is
the method with which the material expansion is controlled and/or
confined. The effect of containment on dilatancy can easily be
demonstrated by using rice to represent the ceramic armor and a
pencil to represent the projectile. The rice depicts unevenly
shaped fractured ceramic pieces. If a pencil is pressed down into a
beaker filled with rice, resistance against the pencil is low. As
the pencil is pushed down farther into the beaker, the rice
continues to move around and away from the pencil by moving into
the unoccupied space provided by the beaker. This space is upward
toward the top of the beaker, and through voids between unevenly
filled and distributed rice orientation within the beaker.
[0112] However, if the rice is confined to a flask with a narrow
neck, the resistance to the pencil will be much greater as the rice
is unable to quickly move out of the way of the pencil. This is due
to the bottle-necked restriction of the flask. The free volume for
expansion has now been mitigated allowing for a greater resistance
to the pencil. Controlling the fractured ceramic pieces in armor
further confines the ceramic and only allows for the coarse highly
abrasive ceramic to grab against the penetrator, thereby reducing
its ability to effectively penetrate through a combination of the
resistance, hardness, strength, and friction associated with the
abrasiveness of the ceramic material. This further works against
the penetrator to aid in erosion of the core, and allowing for the
angle of incidence relative to impact, to change upon the
projectile core through the penetration phase. Typically,
unconstrained ceramic armors simply blow away on impact with little
or no abrasive and destructive effect on the projectile. However, a
properly designed armor system that totally constrains any
fractured ceramic material will provide for continued resistance to
that projectile as highly erosive ceramic particles are precluded
from separating a great distance and grind at the sides of the
projectile eroding it and its energy.
[0113] The extremely hard, strong, and tough AP penetrators
combined with their mass and velocity, always impart higher
dilatancy rates than other types of bullet configurations.
Containing and controlling the ceramic dilatancy is the primary
part of the essential mechanics of dwell and interface defeat--the
phenomenon where an impacting projectile flows radially outward
(erodes) along the surface of the target without significant
penetration. During dwell, the projectile loses kinetic energy due
to mass loss and deceleration.
[0114] This pre-penetration phase delineates a series of events
from the initial interactions of the projectile and the ceramic
facing component of the armor system prior to the projectile
actually entering into the ceramic. During this phase the high
hardness of the ceramic overmatches the impact load of the
projectile and its material composition, which in turn causes the
projectile to dwell upon the surface of the ceramic creating
disintegration of the projectile's meplat, jacket and ogive section
of the core.
[0115] This initial disintegration and/or comminuted damage of the
projectile is directly related to the impact stress loads applied
to the projectile from the impact which in turn leads to the
erosion, fracture, and subsequent brittle fracture shattering
and/or core component separation, and the pulverization of the
meplat.
[0116] The time history of this pre-penetration phase ranges
roughly from 0 to 10 milliseconds before the projectile starts to
enter through the surface of the ceramic as the hardness and
fracture toughness stress capabilities of the ceramic is exceeded
and the material failure phase starts with the remaining
penetration transition velocity of the projectile core.
[0117] The Armor and projectile material failure phase starts
roughly from 10 milliseconds and goes through approximately 18
milliseconds. This phase defines the exact condition of the
penetrator as a result of dwell time resistance that leads to the
eroding, fracturing and core component shattering and/or
separation. Additionally, this defines the ceramic armor and its
ability to attenuate and absorb the projectile momentum and energy
while maintaining its integrity to resist tensile damage while
grossly limiting compressive damage through a delayed mechanism and
to increase the dwell and lateral shear stress applied to the
penetrator core. The ceramic/polymeric composite armor listed in
various embodiment's of this invention deals with each of these as
a multi-phased component.
[0118] However, another problem facing armor designers is weight.
Ultimately, high threat-defeating body armor may become too thick
and heavy in which to move. As a result, there is a need for body
armor systems that are thin and light, but difficult to penetrate.
Current fielded systems employ ballistic/fragmentation soft
textile-grade fabrics that have rifle-defeating upgrade monolithic
plate(s) attached to or mounted in front of the textile armor
panels. There is very limited flexibility surrounding the plates,
and it is important to note that this limited flexibility around
the plate is often in areas that the body generally does need to
bend or twist. The areas of plate insertion or addition can be as
thick as 1.250''/31.75 mm to 2.0''/50.8 mm depending upon the
composition of the plate, in addition to the textile portion of the
vest. This precludes the wearer from various types of activities
often encountered during deployment, such as rappelling, fast
roping, climbing, underwater diving, running, entering or exiting
vehicles, etc.
[0119] One approach to weight reduction is the modified use of
ceramics, which can provide exceptional protection for very
lightweight (compared to various metallic) configurations and
densities.
[0120] Ceramics have been developed with exceptional hardness,
upwards of RC65, a prerequisite to initiating bullet/projectile
deformation and/or destruction. Some of the relevant
ballistic-grade opaque ceramic materials are aluminum oxide
(Al.sub.2O.sub.3), silicon carbide (SiC), silicon nitride
(Si.sub.3N.sub.4), boron carbide (B.sub.4C), and titanium diboride
(TiB.sub.2), and sialon a high temperature refractory ceramic with
high strength, fracture toughness, and increased hardness, in all
three phases--.alpha. (Me.sub.xSi.sub.12-(m+n)O.sub.nN.sub.16-n),
.beta. (Si.sub.6-zAl.sub.zO.sub.zN.sub.8-z), and the gradient
.alpha./.beta. where there is a higher concentration of harder a
phase on the strike face region and the softer .beta. phase in the
central region, exhibiting higher fracture toughness; all of which
have high hardness with an associated abrasiveness, high
compressive and tensile strengths, and good elastic properties to
high stress values. Additionally, hybridized ceramic compositions
of boron carbide with silicon carbide, or sialon with silicon
carbide are just two more examples of applicable ceramic
compositions capable for utilization within the scope of this
invention.
[0121] Compared to metals, opaque or transparent ceramics have the
following relative characteristics: [0122] brittleness, [0123] high
strength and hardness, especially at elevated temperatures, [0124]
high elastic modulus, [0125] low toughness, and [0126] density and
thermal expansion.
[0127] However, due to the wide variety of ceramic material
compositions (inclusive of constituent enrichment
minerals/materials for increased physical and mechanical
properties), and grain sizes, the mechanical and physical
properties of ceramics vary significantly. Ceramics are inherently
sensitive to flaws, defects, surface or internal cracks, different
types and levels of impurities, porosity, and manufacturing
processes, and can have a wide range of properties. Such inherently
adverse characteristics can, however, be manipulated through
various manufacturing processes to bring the physical and
mechanical properties in line with the requisite requirements
necessary for ballistic resistance at a substantially low areal
density. Ceramic composites will, for the most part, be somewhat
thicker as compared to most metallurgical armor systems in the
final configuration when coupled with the appropriate fracture
control material backings, etc.
[0128] Two of the prime advantages of the use of ceramics over
other materials are the extreme hardness and light weight.
[0129] Associated ballistic-grade ceramic types and their
approximate weight differences are:
[0130] Material Characteristics
Aluminum Oxide--Al.sub.2O.sub.3 Primary ballistic-grade opaque
ceramic; least manufacturing cost; approximate density 3.4-3.6
g/m.sup.3. Silicon Carbide--SiC approximate density 3.1 g/m3.
Silicon Nitride--Si.sub.3N.sub.4 approximate density 3.2 g/m3.
SiC/B4C composite hybrid .about.12% lighter than SiC or Si3N4 Boron
Carbide--B.sub.4C approximate density 2.34 g/m3. Titanium
Diboride--TiB.sub.2 approximate density 4.52 g/m3.
Alon--AL.sub.23O.sub.27N.sub.5 approximately 3.69 g/m.sup.3 .alpha.
Sialon--Me.sub.xSi.sub.12-(m+n)O.sub.nN.sub.16-n,
Y.sub.0.4Si.sub.9.6Al.sub.2.4O.sub.1.2N.sub.14.8,
Ca.sub.xSi.sub.12-3xAl.sub.3xO.sub.xN.sub.16-x, others not
presented for brevity, approximately 2.53-3.26 g/m3
.beta.Sialon--Si.sub.6-zAl.sub.zO.sub.zN.sub.8-z,
Si.sub.5.55Al.sub.0.45O.sub.0.45N.sub.7.55, others not presented
for brevity. approximately 2.53-3.26 g/m3 Saphire--AL.sub.2O.sub.3
approximately 3.97 g/m.sup.3 Spinel--MgAl.sub.2O.sub.4
approximately 3.59 g/m.sup.3
[0131] Limited gains have been achieved utilizing silicone carbide,
however, the technology has reached a point where the offset gains
are better than the standard increased areal density ballistic
grade ceramics, but all six opaque types, and all four transparent
types should be considered for a type of embodiment regarding
ceramics.
[0132] Numerous advances have been achieved in reducing the areal
density of ceramic composite systems. The majority of these efforts
have been directed in two distinct directions: 1) synthesizing new
ceramic materials with improved mechanical properties, and 2)
synthesizing backing materials with increased rigidity to enhance
support of the ceramic component. However, an alternative approach
of reducing the areal density of a ceramic composite armor system
is to utilize a ceramic/polymer structure system where the ceramic
component are supported by the polymer component as opposed to a
layered laminated ceramic/polymer structure such as those utilized
in transparent armor applications. One of the primary advantages of
such a ceramic armor system as compared to the layered laminated
ceramic/polymer structure such as those utilized in transparent
armor applications is its ballistic resistance performance
capability to defeat such threats as the depleted uranium and
tungsten heavy alloy penetrators.
[0133] Containment Substrate Attributes
[0134] Another approach to weight reduction has been the use of
composite materials such as reinforcing fibers and the matrix
materials utilized to form lightweight composites. These fibers are
strong and stiff, and they have high specific strengths
(strength-to-weight ratio) and specific stiffnesses
(stiffness-to-weight ratio). The fibers by themselves have little
structural value. The polymer matrix is less strong and less stiff,
but it is tougher than the fibers. Reinforced polymeric resin
composites possess the advantages of each of the two
constituents.
[0135] The percentage of fibers (by volume) in reinforced polymers
usually ranges between 10% and 60%. Practically, the percentage of
fiber in a matrix is limited by the average distance between the
adjacent fibers or particles. The highest practical fiber content
is .about.65%; higher percentages generally result in lower
structural properties.
[0136] In addition to high specific strength and specific
stiffness, reinforced-polymeric composite structures have improved
fatigue resistance, greater toughness, and higher creep resistance.
Matrix materials are usually thermoplastics or thermosets; they
commonly consist of epoxy, polyester, fluorocarbon,
polyethersulfone, or silicone.
[0137] The matrix in a reinforced polymer composite has three
functions: [0138] to support the fibers in place and transfer the
stresses to them, while they carry most of the load, [0139] to
protect the fibers against physical damage and the environment, and
[0140] to reduce the propagation of cracks in the composite, by
virtue of the greater ductility and toughness of the polymer
composite matrix.
[0141] The primary focus with reinforced polymers is to allow for
the ductility and elongation of the fibers, while maintaining the
toughness of the matrix material. This is completed with the proper
selection of matrix polymeric materials that provide for the best
overall performance characteristics of the total matrix constituent
materials and the fibers/fabrics through controlled
delamination.
[0142] Providing for a controlled delamination of woven textiles is
slightly altered from that of the matrix polymeric material and is
designed to aid in the composition being manufactured with very
little resin matrix, which reduces weight and relies heavily upon
the ultimate strengths and elongation mechanisms of the
fibers/fabrics to provide for the defeat mechanism during the
ballistic impact. Too much resin composite matrix inhibits the
elongation requirements of the fabrics/fibers and results in poorer
ballistic performance, and increased weights.
[0143] Fiber-reinforced textile armors are not limited solely to
the matrix-reinforced polymeric composite designs and formulations.
Aramids, para-aramids, carbon fiber, glass fiber, and polyethylene
fabrics are often used in standalone configurations such as soft or
hard rigid armor with ballistic resistance capabilities. Often
hybridized/composite configurations are designed to have a greater
penetration resistance-to-weight ratio, albeit at a higher nominal
thickness than matrix reinforced composites.
[0144] The percentage of resin matrix by volume for woven materials
would be from 12 to 18% for aramids, with the highest performance
tested embodiment having 14.5% and from 34% to 40% with the highest
performance tested embodiment having 38% for E-Glass/S2 glass
configurations. These percentages are based on the materials
physical and mechanical property attributes for elongation of yield
through a controlled delamination.
[0145] Additional fiber/fabric materials utilized in various
embodiments in addition to the aramids and para-aramids are the use
of carbon fibers, woven stainless steel textile, woven non-magnetic
nitinol textile, E-Glass, S2 glass; as well as nano-infused aramid,
carbon fibers and para-aramid textiles, E-Glass and S2 glass.
[0146] Ceramic/Polymer Attributes
TABLE-US-00001 Ceramic/Polymer Composition Type by Figure Pros Cons
2 Lightest Weight, Good Dilatancy Biased Configuration, Disc
Control Orientation Prerequisites, Increased QC requirements 3
Improved Dilatancy Control Biased Configuration, Increased
Fabrication Costs, Disc Orientation Prerequisites, Increased QC
requirements, Increased Weight 4 Lighter Weight, Reduced Limited
dilatancy control, Fabrication Costs, Reduced QC Increased
Thickness requirements 5 Improved Dilatancy Control, Increased
Weight, Increased Reduced QC requirements Manufacturing Costs 6
Lighter Weight, Titanium Biased Configuration, Disc Encasement
Orientation Prerequisites, Increased QC requirements, Increased
Manufacturing Costs 7 Better Dilatancy Control, Reduced Increased
Weight, Increased Fabrication Costs, Titanium Thickness, Increased
Encasement Manufacturing Costs 8 Greatest Dilatancy Control,
Reduced Increased Weight, Increased QC requirements, Titanium
Manufacturing Costs Encasement 9 Lighter weight, Titanium Increased
weight and encasement, Great dilatancy control manufacturing costs
over type 10, increased thickness 10 Lightest weight, Reduced QC
Limited dilatancy control, requirements increased thickness 11
Lighter weight, increased core Increased weight over type erosion.
10, increased costs. 12 Light weight, titanium encasement,
Increased weight and great dilatancy control manufacturing costs
over type 11, increased thickness.
[0147] Nano-Composite Attributes
[0148] Newer pretested nano-ceramics have demonstrated limited
promise, as the ceramic is infused with carbon nano-materials. The
long tube shaped nano-materials (CNT's) do not perform nearly as
well as the "bucky-ball" shaped nano-materials. The CNT materials
tend to fail in lateral shear stress instances and often pull-out
under brittle facture failure like the whisker shaped E-glass, S-2
glass and aramid materials used in the reinforcing of ceramics as
an aid to increasing fracture toughness. Nano infused ceramics tend
to induce failure in the ceramics due to the carbonaceous defects
of the nano-materials themselves which for most part are purely
carbon, which in-turn directly affects the fracture path and mode
of fracture morphology.
[0149] Experimental evidence shows that some nano-composites with
special matrices and filler materials, and nanostructured polymeric
composites have achieved significant and simultaneous improvements
in stiffness, fracture toughness, impact energy absorption and
vibration damping, for textile, resin, polymer and copolymer
materials; and these characteristics could be of particular
importance for impact energy absorption based on important
influence factors, such as shape, dimension and stiffness of
particles, type of matrix, particle volume fraction, distribution
of particles and the particle-matrix interfacial properties. These
would be useful upon full production capability for various
embodiments of this invention. However, as of this application none
of these has yet reached the full maturity for production, let
alone finite validation of the ballistic and/or fragmentation
threat resistant performance capabilities.
[0150] Polymeric Material Attributes
[0151] Amorphous polymers have been used extensively as the
structural material of engineering components that are designed to
resist impact, ranging from bus windows and eyeglasses to helmets
and body armor. The choice of polymeric materials for these
applications has been made appealing by their relative low density,
as well as the transparency that is characteristic of amorphous
homopolymers. Thermoplastic polymers are distinctly divided into
two classes of crosslinked (non-linear), and uncrosslinked
(linear). Crosslinked polymers are typically utilized as high
strength or in other specialty polymers, where the uncrosslinked
polymers gain their advantage through the ease of forming
"moulding" configurational shapes of varying dimensions without
unrealistic production costs. Crosslinking is a process by which
the degree of molecular re-arrangement of molecules can be
manipulated. However, transparency in a polymer for this invention
is not a prerequisite. Polymers, unlike glass and ceramics, are
viscoelastic materials, and exhibit strong rate-sensitivity not
only in mechanical deformation, but also in failure behavior. One
prerequisite for an armor system would be the nonlinear
viscoelastic deformation mechanisms and the associated dynamics in
polymers during and immediately following a ballistic impact.
Polymers due to their viscoelastic behaviors, generate heat under
cyclic deformation which raises the temperature if the rate of heat
generation exceeds the heat flow to the surroundings resulting in
fatigue loading failure. This characteristically high temperature
sensitivity of the mechanical properties of polymers provides
validation of hysteristic heating which can have a dominant effect
on the failure behavior under cyclic loading. This hysteristic
failure behavior can create excessive softening of the bulk
material thereby ensuring failure by deformation without fracture
to the result of localized heating at the tip/point of a tensile
fracture or crack accompanied by a redistribution of the stresses
and the complicated resultant failure mechanisms. Utilizing the
ceramic constituent components to abate this hysteristic failure
behavior will increase the multi-repeat hit capability of a
ceramic/polymer composite architecture.
[0152] Polymers exhibit strong rate-dependent mechanical behavior
and in different frequency regimes, the rate sensitivities of
polymers change as various primary (.alpha.) and secondary (.beta.)
molecular mobility mechanisms are accessed. An extensional shock
wave is a disturbance or oscillation that travels through a medium
or multiple mediums which is accompanied by a transfer of energy,
which imparts deformation in the medium. The deformation reverses
itself owing to restoring forces resulting from its deformation,
however, brittle media tends to degrade through brittle fracturing
where ductile media tend to remain plastically deformed or regain
some of the initial pre-shock induced form.
[0153] High stress induced tensile fracture/crack velocity is
usually measured as a function of the stress intensity factor such
as that in an elastomeric fracture, assuming a continuous
fracture/crack propagation in the polymer constituent component as
compared to the brittle failure response of the tensile fracture in
a ceramic material. High stress induced tensile fracture/crack
behavior under cyclic loads can comprise the differentiation
between continuous and discontinuous propagation/growth, the
effects of temperature changes, both due to the environment and the
ballistic impact mechanisms themselves, the frequency of the stress
applied loading and the loading range. Polymer tensile
fracture/crack propagation in rigid polymers exhibit nonlinear
material responses which on a macroscopic level exhibit those
similar to metallic plasticity/ductility. However, metallic
plasticity/ductility in contrast to elastomeric polymers, does not
have a strong influence on the rate of propagation/growth per cycle
unless it is so high that dissipative heating performs a distinct
role. Fracture/crack velocity on a time basis is almost
proportional to the frequency. Tensile fracture or crack
propagation/growth behavior in polymers can be uniquely different
to that of metallic systems where the fracture/crack propagates a
specific distance with each cycle depending upon the stress
intensity range. In polymers, the fracture/crack may not even
propagate of many cycles from one to several hundred, but in the
latter case would then jump or propagate in a substantial "jump
ahead" by a specific amount depending on the size of the stress
intensity range.
[0154] Controlling the extensional shock wave propagation transfer
from one dissimilar material to another is required to preclude
composite armor deterioration during the ballistic impact in the
regions surrounding the epicenter of the projectile core trajectory
from force tensile stress fracturing. Inertia and the inner
kinetics of the materials used in a composite is a vitally
important factor, and the dynamic induced deformation of the
materials is often created by the extensional wave propagations and
transference, which can either be mitigated by the dissimilar
materials or amplified though the rapid delivery of the high
mechanical stress/strain energy transfer during the ballistic or
fragmentation impacting event.
[0155] Precluding the molecular deterioration from the stress
induced extensional shock wave transfer is germane to the
development of any high-performance armor material substrate. The
secondary effects of this are additionally prevalent due to the
fact that the rheological effects of the armors loading required to
resist failure is translated into the personnel wearing the armor
or the mechanical, electrical, pneumatic pressurized gas or
hydraulic pressurized fluid transfer systems of an aircraft,
vehicle or vessel. This is more so in personnel as shock wave
propagation is easily continued or amplified by tissues, organs,
biopolymers and gels due to either the fluid content or the
amorphous state of a solid, which are comprised of particles atoms,
grains, bubbles, molecules, which are arranged so that the
locations of their centers of mass are disordered; thereby
arranging their structure in a manner that is essentially
indistinguishable from a liquid.
[0156] A ballistic impact will create an extensional shock wave
which is a violent disturbance in the equilibrium of an armor
system. They are in fact high-speed, large amplitude mechanical
transients generated by a time dependent violent impact. The
dynamics of structural changes induced by ballistic impact and that
dissipation of mechanical energy on the dynamic time scale of the
extensional shock wave event are of obvious concern for the
appropriate design and effectiveness of any protective armor system
and its constituent materials.
[0157] The extensional shock wave travels through a material at a
velocity (Ua) equal to the sum of the particle velocity (Up) and
the substrate medium's acoustic velocity .COPYRGT.:Ua.apprxeq.Up+c.
The particle velocity is the speed with which the armor material at
the point of impact is repositioned, and the velocity of the armor
material flow behind the primary extensional shock wave. Any region
impacted directly by the extensional shock wave transfer will
demonstrate a higher density than the regions less effected by the
extensional shock wave transfer specifically due to the
hierarchical structural arrangement of ballistic component zones.
The cause of an extensional shock wave transfer in a material's
property is that it transmits sound quicker with increased pressure
(density). The fundamental prerequisite for the creation of an
extensional shock wave transfer is that the velocity of the pulse
(Us), increases with increasing pressure (P) (density) of any
constituent material.
[0158] The extensional shock wave impulse in both the longitudinal,
transverse (shear), and diagonal directions coupled with the
wavelength dimensions and amplitudes themselves, create numerous
rebound complexities due to the multitude of colliding points from
outbound and inbound reflected impulses.
[0159] The amplitude of a shock wave may be constant (in which case
the wave is a continuous wave), or may be modulated so as to vary
with time and/or position. The outline of the variation in
amplitude is called the envelope of the extensional shock wave.
[0160] A shock wave can be transverse or longitudinal depending on
the direction of its oscillation.
[0161] Transverse shock waves occur when a disturbance creates
oscillations perpendicular (at right angles) to the propagation
(the direction of energy transfer). Longitudinal waves occur when
the oscillations are parallel to the direction of propagation.
While mechanical waves can be both transverse and longitudinal,
mechanical shock waves propagate through a medium, and the
substance of this medium is deformed. The deformation reverses
itself owing to restoring forces resulting from its deformation.
For example, sound waves propagate via air molecules colliding with
their neighbors. When air molecules collide, they also bounce away
from each other (a restoring force). This keeps the molecules from
continuing to travel in the direction of the wave.
[0162] The extensional shock wave transfer velocity rates are used
to determine elastic constants through both longitudinal and shear
velocities. For various embodiments of this invention, the primary
material substrate backings are:
Polyethylene--
[0163] V.sub.L=2,430 F.P.S. [0164] Vs=946 F.P.S.
Polystyrene--
[0164] [0165] V.sub.L=2,350 F.P.S. [0166] Vs=1,120 F.P.S.
Polycarbonate--
[0166] [0167] V.sub.L=2,200 F.P.S. [0168] Vs=910 F.P.S.
Polyurethane--
[0168] [0169] V.sub.L=2,559 F.P.S. [0170] Vs=1,049 F.P.S.
Polymethyl methacrylate (PMMA)-- [0171] V.sub.L=2,690 F.P.S. [0172]
Vs=1,344 F.P.S.
[0173] Where: B=Bulk modulus, G=shear modulus, and P=Density
[0174] V.sub.L--is the velocity of plane longitudinal shock wave in
bulk material, with the velocities in feet per second. (1)
V.sub.L= {square root over ((B+4G/3/p)}
[0175] Vs--is the velocity of plane transverse (shear) shock wave,
with the velocities in feet per second. (2)
V.sub.s= {square root over (G/p)}
[0176] For an isotropic solid, such as the various polymers listed
in the embodiments of this invention, there are only two
independent elastic constraints. These two can be taken to be G and
B, but it is sometimes convenient to use other elastic constants,
such as Young's modulus, Y, and Poisson's ratio, .sigma..
[0177] These constants can be calculated using the standard
relations:
Y = 3 G 1 + G / 3 B ( 3 ) .sigma. = 1 2 - Y 6 B ( 4 )
##EQU00001##
[0178] The four constants G, B, Y and .sigma. are referred to as
engineering constants. Other constants are also used, and they can
be calculated from the engineering constants. For example, the
Lame' constants .mu. and .lamda. are given by:
.mu.=G (5)
.lamda. = B - 2 3 G ( 6 ) ##EQU00002##
[0179] The elastic constants can also be expressed using the
elastic stiffness matrix. In generalized form, Hook's law is given
by:
.sigma. i = i = 1 6 cij j ( 7 ) ##EQU00003##
[0180] Where the .sigma.I are the stress components, the ci are the
strain components, and the cij are the isothermal elastic stiffness
coefficients.
[0181] For an isotropic solid:
c44=c55=c66=G (8)
c11=c22=c33=B+4G/3 (9)
c12=c13=c23=c21=c31=c32=B-2G/3. (10)
[0182] All other coefficients are zero. If any other constants are
desired, they can be calculated using the equations (5) to
(10).
[0183] Impacting shock waves exhibit eight common behaviors within
typical standard conditions. They are: the media through which the
shock waves are transmitted and the type of transmission;
absorption capabilities of the media; reflection by which a shock
wave may be re-directed relevant to the angle of incidence of the
shock wave direction; interference that may be encountered when two
shock waves superimpose upon each other to form a new shock wave;
refraction when the shock wave transfers from one media to another,
thereby changing the directional velocity of the shock wave;
diffraction of the shock wave when it encounters an obstacle that
bends the shock wave or spreads it after emerging from an opening
in the media; dispersion of the shock wave; and polarization if the
shock oscillates in a single direction or plane. Polymers exhibit
two distinct types of fracture/crack propagation responses: one
where the crack propagation moves in a "near-rigid" polymer (crack
propagation velocity >39''/1 m-min), or in a strongly
viscoelastic polymer material (crack propagation velocity
<39''/1 m-min).
[0184] The behavior of the thermoplastic polycarbonate has been
investigated in both longitudinal and lateral orientations. These
have been used to determine the impacting shock stress, shock wave
velocity, particle velocity, release velocity and shear strength.
The relationship between shock velocity and particle velocity has
been shown to be linear. Shear strength has been observed to
increase behind the shock front, a feature observed in other
polymers such as Polymethl methacrylate (PMMA) or polyether ether
ketone (PEEK). It also increases with stress amplitude, although
the projected intercept with the calculated elastic response
indicates that the Hugoniot elastic limit (HEL) is lower than in
other polymers, for example PMMA (ca. 0.75 GPa) or PEEK (ca. 1.0
GPa). This further suggests that the yield strength of
polycarbonate does not obey a Mohr-Coloumb criterion, and hence is
not as strongly pressure dependent as other polymers.
[0185] Polycarbonate (PC)
##STR00001##
[0186] The paramount ballistic resistant armor polymer, mass
produced on the market today is polycarbonate (PC) based
(Lexan.RTM.). Armor laminates using Lexan.RTM. are currently in
service throughout the military and law enforcement sectors,
however, their effectiveness is ultimately limited by their impact
strength.
[0187] Polycarbonate is a polymer which is used for lightweight
transparent armor in a wide range of applications. This material
has an unusually high yield strain and ductility; this combined
with a significant amount of strain hardening enables it to display
impressive impact and perforation resistance. Polycarbonates have
also shown benefits to the physical and mechanical structure
changes required for high impact resistance, once going through a
hot drawn process if kept within the 10 to 15% hot drawn percentage
draw ratio.
[0188] Polycarbonate polymer is produced by reacting bisphenol A
with phosgene. Polycarbonate typically exhibits five mechanisms of
deformation and subsequent fracture during the terminal ballistic
impact with handgun projectile threats and velocities. They are:
elastic dishing, petalling, deep penetration, cone cracking and
plugging. Thin plates impacted by spherical missiles exhibit
elastic dishing, whereas thick plates suffer a deep penetration
process. In both cases, final failure is by petalling. Cylindrical
missiles impacting thick plates also cause deep penetration with
final failure occurring by plugging. For thin plates impacted by
cylindrical missiles, cone cracking develops from the leading edge
of the missile.
[0189] Recent unpatented industry research on polycarbonate
improvements at the Shell Chemical Company has led to the
development of a co-polyester derived from
2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO), 1,3-propanediol
(PDO), and dimethyl terephthalate (DMT). By varying the percent
incorporation of the monomers, the thermal/mechanical properties of
this copolyterephthalate are tunable. Shell found that interesting
impact properties arose from the material when 40 mol % CBDO was
incorporated into the polymer. This material displayed a notched
Izod value of 1070 J/m while maintaining T.sub.g near 100.degree.
C. This new material shows improvement over bisphenol A
polycarbonate in both notched Izod as well as ballistic impact
values.
[0190] Polycarbonate: an amorphous polymer made by SABIC Innovative
plastics (GE Plastics) under the tradename Lexan.RTM., and Bayer
material Science under the trade name Makrolon.RTM.. Other
secondary manufactures are listed in Appendix A.
[0191] Polymethyl Methacrylate (PMMA)
##STR00002##
[0192] Polymethyl methacrylate (PMMA) has seen widespread use in
applications such as lightweight transparent enclosures for
aircraft and as added spalling components for personnel. PMMA,
however, while much tougher and more impact resistant than glass,
is relatively brittle and it too, will spall upon ballistic impact,
leading to possible injury to personnel behind the PMMA armor.
Thermal, morphological, and mechanical properties of PMMA
copolymers have been proven as well as the changes in highly hot
drawn techniques, have demonstrated improved ballistic impact
performance. PMMA is not as hard as glass, yet its extraordinary
response in mechanical strengthening at high rates results in a
drastic increase in the effective hardness.
[0193] Polymethylmethacrylate: an amorphous polymer made by the
Rohm and Haas Company, Philadelphia, Pa., under the trade name
Plexiglas.RTM. II UVA. Other secondary manufactures are listed in
Appendix A.
[0194] Polyurethane (PU)
##STR00003##
[0195] Polyurethane is a polymer composed of a chain of organic
units joined by carbamate (urethane) links. While most
polyurethanes are thermosetting polymers that do not melt when
heated, thermoplastic polyurethanes are also available.
[0196] Polyurethane polymers are formed by reacting an isocyanate
with a polyol. Both the isocyanates and polyols used to make
polyurethanes contain on average two or more functional groups per
molecule.
[0197] Polyurethanes are in the class of compounds called reaction
polymers, which include epoxies, unsaturated polyesters, and
phenolics. Polyurethanes are produced by reacting an isocyanate
containing two or more isocyanates groups per molecule
(R--(N.dbd.C.dbd.O)n.gtoreq.2) with a polyol containing on average
two or more hydroxy groups per molecule (R'--(OH)n.gtoreq.2), in
the presence of a catalyst. The most commonly used isocyanates are
the aromatic diisocyantes, toluene diisocyanate (TDI) and methylene
diphenyl diisocyanate, MDI.
[0198] The properties of a polyurethane are greatly influenced by
the types of isoyanates and polyols used to make it. Long, flexible
segments, contributed by the polyol, produce a soft, elastic
polymer. High amounts of crosslinking produce tough or rigid
polymers. Long chains and low crosslinking produce a polymer that
is very stretchy, short chains with lots of crosslinks produce a
hard polymer while long chains and intermediate crosslinking
produce a polymer useful for making foam. The crosslinking present
in polyurethanes means that the polymer consists of a
three-dimensional network and molecular weight is very high. In
some respects a piece of polyurethane can be regarded as one giant
molecule. One consequence of this is that typical polyurethanes do
not soften or melt when they are heated as they are thermosetting
polymers. The choices available for the isocyanates and polyols, in
addition to other additives and processing conditions allow
polyurethanes to have the very wide range of properties that make
them such widely used polymers.
[0199] Isocyanates are very reactive materials. This makes them
useful in making polymers but also requires special care in
handling and use. The aromatic isocyanates, diphenylmethane
diisocyanate (MDI) or toluene diisocyanate (TDI) are more reactive
than aliphatic isocyanates, such as hexamethylene diisocyanate
(HDI) or isophorone diisocyanate (IPDI). Most of the isocyanates
are difunctional, that is they have exactly two isocyanate groups
per molecule. An important exception to this is polymeric
diphenylmethane diisocyanate, which is a mixture of molecules with
two-, three-, and four- or more isocyanate groups. In cases like
this, the material has an average functionality greater than two,
commonly 2.7. Isocyanates with functionality greater than two act
as crosslinking sites as mentioned in the previous paragraph.
[0200] Polyols are polymers in their own right and have on average
two or more hydroxyl groups per molecule. Polyether polyols are
mostly made by polymerizing ethylene oxide and propylene oxide.
Polyester polyols are made similarly to polyester polymers. The
polyols used to make polyurethanes are not "pure" compounds since
they are often mixtures of similar molecules with different
molecular weights and mixtures of molecules that contain different
numbers of hydroxyl groups, which is why the "average
functionality" is often mentioned. Despite the fact they are
complex mixtures, industrial grade polyols have their composition
sufficiently well controlled to produce polyurethanes having
consistent properties. As mentioned earlier, it is the length of
the polyol chain and the functionality that contribute much to the
properties of the final polymer. Polyols used to make rigid
polyurethanes have molecular weights in the hundreds, while those
used to make flexible polyurethanes have molecular weights up to
ten thousand or more.
[0201] Copolymer
[0202] A copolymer or rheteropolymer is a polymer derived from two
(or more) monomeric species, as opposed to a homopolymer where only
one monomer is used. Copolymerization refers to methods used to
chemically synthesize a copolymer. Copolymerization is used to
modify the properties of manufactured polymeric materials to meet
specific needs, for example to reduce crystallinity, modify glass
transition temperature or to improve solubility. It is a way of
improving mechanical properties, in a technique known as rubber
toughening. Elastomeric phases within a rigid matrix act as crack
arrestors, and so increase the energy absorption when the material
is impacted.
[0203] Block copolymers are generally defined as macromolecules
with a linear and/or radial arrangement of two or more different
blocks of varying monomer compositions. Block copolymers are
interesting as they can "microphase separate" to form periodic
nanostructures. Block copolymers consist of two or more chemically
distinct polymer chains (blocks) linked by covalent bonds. These
blocks can micro-phase separated into nanometer-sized domains whose
structure depends upon the size and interactions of the blocks.
Block copolymers can also control the ordering of inorganic
precursors that selectively associate with one block. The
importance of block copolymers can be seen in their wide array of
properties. These properties are made possible due to the
combination of different polymers in alternating sequence. Due to
the rapid progress in these areas block copolymers now stand on the
verge of a new generation of sophisticated materials applications,
in which particular nanostructures will play a crucial role in
armor applications.
[0204] Polyurethane based energy absorbing copolymers and block
copolymers are a recent development and have improved the
fragmentation and blast resistance of lightweight polymeric based
single constituent armors, including but limited to acrylics,
polycarbonates, polynethyl methacrylates, and hybridized composite
systems of either.
[0205] In an extension of previous work on polyurethane block
copolymers for transparent armor applications, several additional
variations of the basic 2,4-toluene diisocyanate/polytetramethylene
oxide/1,4-butanediol formulation have been investigated. It has
been found that excess diisocyanate in a given formulation improves
ballistic resistance and that decreasing the amount of polyether
(soft segment) has the same effect. More generally, it has been
found that increased sample hardness (Shore D) parallels improved
ballistic performance. High-speed photographic data has shown that
these materials continue to absorb large amounts of ballistic
energy, with relatively little of this energy manifested as
fragment kinetic energy. A technique for the preparation of
void-free ballistic resistant specimen involving the use of a
polytetrafluoroethylene mold is also described; and a technique for
a zero VOC ballistic resistant void-free cast specimen.
[0206] In one embodiment, one specific type of synthesized polymer
that was tested, was a solid polyurethane zero VOC polymer cured
material in which demonstrated definite "standalone" performance
capabilities had the following mechanical and physical properties
test results:
[0207] Cured Flexibility
[0208] -40F 1/2 Mondreal Bend 74%
[0209] -60F 1/2 Mondreal Bend 76%
[0210] -40F Elongation 2.4%
[0211] -60F Elongation 1.8%
[0212] Ambient 72F 7.7%
[0213] Strength/Impact Resistance
[0214] Tensile Strength 1,892 PSI
[0215] Compression 1 hour 27,740 PSI
[0216] Recovery at Ambient 87.4%
[0217] This type of polymer was mixed and cast (it is a two part
voc polyurethane resin in which the poliol has been tweaked)
on-site and poured into 2''.times.3''.times.4'' blocks. The
strength and compression tests were conducted on the thin 2'' face.
Ceramics or other organic particles can be added into the
mixture.
[0218] The other material properties and compositions are:
[0219] Basic Physical Properties within matrix
[0220] Iso 100 parts
[0221] Polyol 50 parts
[0222] Iso visc 3000 mpa Brookfield
[0223] Polyol visc 150 mpa Brookfield
[0224] Pot life 15 min. set 150 gms pour in place
[0225] Cured Mechanical/Physical Properties
[0226] Shore D 60
[0227] Tensile Modulus Mpa 630
[0228] Tensile Mpa 27
[0229] Elongation at break 120%
[0230] Flexural Modulus Mpa 450
[0231] Flexural Strength Mpa 28
[0232] Tear Strength 84
[0233] Impact Strength Charpey KMm2--unbreakable
[0234] Resilliance Bay Shore test 62%
[0235] Abrasion 1000 rev HZZ wheel 54
[0236] Polymer Testing
[0237] The limited testing that was completed consisted of two
projectile types.
[0238] The first was a sharp pointed rod shaped projectile and the
second was a rounded sphere projectile.
[0239] Stainless steel dart fired from 26' at 109,000 PSI-- 3/16''
penetration; 20 mm Ball Bearing fired from 26' at 4,750 FPS--3/8''
penetration.
[0240] In one embodiment, one specific type of synthesized polymer
was a polytetramethylene oxide based solid, void-free ballistic
resistant specimen involving the use of a pour in cast mold. Each
formation contained 2,4-toluene diisocanate (TDI),
polytetramethylene oxide (PTMO) and 1,4-butanediol (BD).
The optimal results were attained from the following formulas:
TABLE-US-00002 Composition Cure Temperature Ballistic V.sub.50
velocity & Test Specimen Mole Ratios Conditions Range of
Results 1 TDI 5.25 212.degree. F./100.degree. C. overnight V.sub.50
- 950 F.P.S/290 M.P.S. #03222005 PTMO 1070-1.0 ~12 Hrs. ROR - 73
with 6 impacts BD 4.0 2 TDI 5.25 140.degree. F./60.degree. C.
overnight V.sub.50 - 900 F.P.S/274 M.P.S. #10092005 PTMO 1090-1.0
~12 Hrs. ROR - 75 with 10 BD 4.0 impacts. 3 TDI 5.25 72.degree.
F./22.2.degree. C. overnight V.sub.50 - 930 F.P.S/283 M.P.S.
#06142006 PTMO 1090-1.0 ~12 Hrs. ROR - 70 with 10 BD 4.0
impacts.
[0241] The effect of cure duration and temperature have a definite
impact in the substrates overall ballistic performance. All
V.sub.50 data appears to increase steadily with the allotted cure
times. The threat for these specimens was in accordance with the
military standard MIL-P-utilizing the .22 caliber, 17 grain, steel
fragment simulating projectile, with the nominal thickness of each
specimen tested diagnostic sample dimensioned at
4''.times.4''.times.0.25'', with an approximate areal density of
22.0 ounces per square foot. The fragmentation tests revealed that
the performance capability was almost linear with an approximate
18-20 foot per second increase in fragmentation impact defeat
velocity for approximately every 1 ounce per square foot of areal
density increase.
[0242] Additionally, the higher molecular weight of PTMO created a
significant drop in the ballistic performance. It also appears that
the larger or more fully developed domains of the PTMO (soft
segments in the block copolymers) confer upon the entire specimen
by the increased weight percent of soft material in the higher
molecular weight formulation. This observed mechanical performance
capability is reinforced by the increased weight percent of soft
ductile material in the higher molecular weight formulation of the
specimens that exhibited poor ballistic performance resistance
capabilities. The ductile response of the tested specimens lead to
the following characteristics:
[0243] 1. The lower the PTMO molecular weight by volume, the
greater the V.sub.50 velocities were of the impacting threats. 2.
The ductile response during the projectile impact demonstrates the
typical evidence of lack of any radial tensile fracturing and
absence of brittle failure leading to spall or rearward exit of
polymer ejecta/armor substrate towards the protected side. 3. The
water soluble hydrophilic group demonstrated that water absorption
induces a direct impact on the polymeric material hardness. The
higher the content percentage of water absorption, the lower the
modulus will be of the material, and generally not uniformly
throughout the specimen. The water performed in much the same
manner as a plasticizer would. Decreasing the modulus results in
decrease hardness. It was also determined that "drying" the
polymers through a process of ambient desiccation would remove the
moisture content and limited hardness, but could not eliminate of
the moisture induced elastic response or ductility, decreasing the
mechanical performance attributes required in an composite armor
material.
[0244] In the last decade, the synthesis techniques have been
widely extended, and primarily ionic and controlled free radical
methods can now be employed to prepare block copolymers with
well-defined compositions, molecular weights and structures with
varying elaborate architectures.
[0245] The increasing interest in block copolymers arises mainly
from their unique solution and associative properties as a
consequence of their molecular structure.
[0246] There is almost no limit to the design and optimization for
novel types of block copolymers and of new structures. For example,
several embodiments of this invention include: metal containing
co-polymers, ceramic containing copolymers, metal/ceramic hybrid
containing polymers, metal containing nano-reinforced co-polymers,
ceramic containing nano-reinforced copolymers, metal/ceramic hybrid
containing nano-reinforced polymers, metal containing mixed
media-reinforced co-polymers, ceramic containing mixed
media-reinforced copolymers, metal/ceramic hybrid containing mixed
media-reinforced polymers, molecularly aligned crosslinked polymers
and/or copolymers, molecularly aligned uncrosslinked polymers
and/or copolymers, etc.
[0247] The increasing interest in block copolymers arises mainly
from their unique solution and associative properties which is a
byproduct of their molecular structure. In particular, their
surfactive and self-associative characteristics leading to micellar
systems are directly related to their segmental incompatibility.
Block copolymer micellization, is a unique process by which to
achieve self-assembled nanoparticles with well-defined
morphologies.
[0248] Block copolymer micellar systems are generally produced by
one of the following two procedures. In the first technique, the
copolymer is dissolved molecularly in a common solvent e.g. that is
`good` for both blocks, and then the conditions such as temperature
or composition of the solvent, are changed in the way that requires
formation of micelles. This is commonly achieved by adding
gradually a selective precipitant of one of the blocks, eventually
followed by stripping the common solvent. An alternative, which
improved upon the first process is the dialysis technique by which
the common solvent is gradually replaced by the selective solvent.
In this second technique, a solid sample of the copolymer is
directly dissolved in a selective solvent; the micellar solution is
left to anneal by standing and/or the annealing process is
accelerated by thermal treatment, eventually under ultrasonic
agitation. These process are necessary to avoid void formation
during the cure process.
[0249] However, through both of these techniques, and depending on
the block copolymer system, an equilibrium situation is not
necessarily reached, especially if the core-forming polymer has a
high glass transition temperature (Tg).
[0250] A micelle is an aggregate of surfactant molecules dispersed
in a liquid colloid. The micelles consist of a more or less swollen
core of the insoluble blocks surrounded by a flexible fringe of
soluble blocks. A colloid is a substance microscopically dispersed
throughout another substance. The dispersed-phase particles have a
diameter of between approximately 1 and 1000 nanometers.
Homogeneous mixtures with a dispersed phase in this size range may
be called colloidal aerosols, colloidal emulsions, colloidal foams,
colloidal dispersions, or hydrosols. The dispersed-phase particles
or droplets are affected largely by the surface chemistry present
in the colloid. Micelles form only when the concentration of
surfactant is greater than the critical micelle concentration
(CMC), and the temperature of the system is greater than the
critical micelle temperature. The formation of micelles can be
understood using thermodynamics, (heat and its relation to energy
and work). It defines macroscopic variables (such as temperature,
internal energy, entropy, and pressure), that characterize the
materials, and defines how they are related and by what laws they
change with time). Micelles can form spontaneously due to a balance
between entropy and enthalpy. For example, in water, the
hydrophobic effect (the observed tendency of nonpolar substances to
aggregate in aqueous solution and exclude water molecules), is the
driving force for micelle formation, despite the fact that
assembling surfactant molecules together reduces their entropy.
[0251] Surfactants are compounds that lower the surface tension (or
interfacial tension) between two liquids or between a liquid and a
solid. Surfactants may act as detergents, wetting agents,
emulsifiers, foaming agents, and dispersants. Surfactants are
usually organic compounds that are amphiphilic, meaning they
contain both hydrophobic groups (their tails) and hydrophilic
groups (their heads). Therefore, a surfactant contains both a water
insoluble, (or oil soluble) component, and a water soluble
component. Surfactants will diffuse in water and adsorb (the
adhesion of atoms, ions, or molecules from a gas, liquid, or
dissolved solid to a surface), at the interfaces between air and
water, or at the interface between oil and water, in the case where
water is mixed with oil. The water-insoluble hydrophobic group may
extend out of the bulk water phase, into the air or into the oil
phase, while the water-soluble head group remains in the water
phase. This alignment of surfactants at the surface modifies the
surface properties of water at the water/air or water/oil
interface.
[0252] Entropy is a measure of the number of specific ways in which
a thermodynamic system may be arranged, often considered as a
measure of progress towards achieving a thermodynamic
equilibrium.
[0253] Enthalpy is a measure of the total energy of a thermodynamic
system. It includes the system's internal energy and thermodynamic
potential, as well as its volume and pressure (the energy required
to "make room for it" by displacing its environment, which is an
extensive quantity). Enthalpy change accounts for energy
transferred to the environment at constant pressure through
expansion or heating.
[0254] One of the most useful properties of micellar aggregates is
their ability to enhance the aqueous solubility of hydrophobic
substances which otherwise are only sparingly soluble in water. The
enhancement in the solubility arises from the fact that the
micellar cores, for classical low molar mass surfactants as well as
for block copolymer micelles, can serve as a compatible
microenvironment for water-insoluble solute molecules. This
phenomenon of enhanced solubility is commonly referred to as
`solubilization`, the ability of micelles to solubilize or
encapsulate various compounds, is important in the binding phase
for mixed media such as ceramics, metals, textiles, etc. This is an
incredibly important prerequisite for composite in that adhesion
from one adhered to another is important for attenuation,
absorption and transference of the extensional shock wave transfer
and the further containment of the brittle ceramic components the
amount of encapsulation and retardation of the ceramics reduced
ability to flex.
[0255] A stiff polymer increases shock wave transmission
propagation and reduces the impacting stresses which in turn
reduces the flexure of the ceramic component through absorption of
energy. Conversely, the reduced stiffness of the polymer
encapsulating component decreases the extensional shock wave
transfer but in turn typically reduces the adhesion between the
ceramic component allowing for increased flexure, which increases
the failure of the brittle ceramic component. A centralized
compromise must be maintained through the proper "mixing" of the
constituent chemicals, while reducing or eliminating insolubility
through the control of solubilization. The quality of the
interlamina bond (adhesion of the ceramic and the polymeric
structure), has a significant influence on the dispersive
characteristics of the extensional shock wave transfer, and the
preclusion of dilatancy of the ceramic constituent components.
[0256] Micelles can in block copolymer compositions change shape
under the influence of external parameters, such as temperature or
solvent composition, leading to other copolymer and block copolymer
structural architectures.
[0257] Therefore, the micellization of block copolymers processed
in a selective solvent of one of the blocks is a typical aspect of
their colloidal properties. In fact when a block copolymer is
dissolved in a liquid that is a thermodynamically good solvent for
one block and a precipitant for the other, the copolymer chains may
associate reversibly to form micellar aggregates which resemble in
most of their aspects to those obtained with classical low
molecular weight surfactants. It is therefore a prerequisite to
ensure an appropriate dissolving technique is utilized as
applicable, for the constituent materials such as stirring under
vacuum or inert gas pressure, etc.
[0258] Great attention has to be paid to the preparation step of
the micellar system. In fact, one has to be aware that the simple
dissolution of the block copolymer in a selective solvent, or even
the preparation of the micellar system by step-wise dialysis could
lead to non-equilibrium situations to so-called `frozen
micelles`.
[0259] Water is absorbed by most polymers resulting in polymer
property changes by the water in various opposing ways at low and
high temperatures, affecting such properties as moduli, changes in
the dampening spectra, and thermal expansion due to the moisture
absorption.
[0260] Polyether Ether Ketone (PEEK)
##STR00004##
[0261] Polyether ether ketone (PEEK), is a colorless organic
polymer thermoplastic, that is manufactured by step-growth
polymerization by the dialkylation of bisphenolate salts. PEEK is a
semi-crystalline thermoplastic with excellent mechanical and
chemical resistance properties that are retained to high
temperatures, and is not traditionally a shape memory polymer;
however, recent advances in processing have allowed shape memory
behavior in PEEK with mechanical activation.
[0262] The behavior of the polymer polyether ether ketone (PEEK)
has been investigated under conditions of one-dimensional shock
loading. This has involved measurement of the Hugoniot in terms of
stress, extensional shock wave velocity and particle velocity, and
measurements of the lateral stress, which have been used to
determine the shear strength, and its variation with extensional
shock wave stresses. Analysis of the relationship between shock
wave velocity and particle velocity shows a simple linear response,
in common with many other materials. Shear strength has also been
shown to increase with shock wave stress. Below this stress, the
material appears to behave in a simple elastic manner. Shear
strength has also been observed to increase significantly behind
the shock front. This behavior has been observed in other polymeric
materials, where it is suggested that these materials were
responding by a viscoplastic mechanism.
[0263] None of these polymeric compositions or hybridized
composites are fully capable of defeating high velocity rifle
defeating threats nor armor piercing or armor piercing incendiary
threats. The limited impact strength coupled with the lack of
hardness preclude that performance resistance capability. Adding a
ceramic composite strike face or ceramic media to the polymeric
composition in a hybridized component system would provide that
performance resistance capability.
TABLE-US-00003 APPENDIX A Polycarbonate Manufacturers Kolon SPELLOY
.RTM. LANXESS Pocan .RTM. Polymer Technology and Services (PTS)
Polymer Technology and Services (PTS) Tristar .RTM. Quadrant
Engineering Plastics Products Quadrant Engineering Plastics
Products Quadrant LSG Quadrant Engineering Plastics Products
Quadrant PC RTP Company EMI RTP Company ESD RTP Company EXT RTP
Company PermaStat .RTM. RTP Company RTP A. Schulman ComAlloy A.
Schulman ComAlloy Comtuf .RTM. A. Schulman ComAlloy Hiloy .RTM. A.
Schulman ComAlloy Lubrilon .RTM. A. Schulman, Inc. ComAlloy .RTM.
A. Schulman, Inc. COMTUF .RTM. Aaron Industries Corporation
AAROPRENE .RTM. AE PC/ABS Aaron Industries Corporation AAROPRENE
.RTM. AEPC Aaron Industries Corporation AAROPRENE .RTM. GFPC ABW
Plastics Aclo Compounders Accucomp Aclo Compounders Accuguard Aclo
Compounders Acculoy Aclo Compounders Accutech Adell Plastics, Inc.
AdvanSource Biomaterials ChronoFlex .RTM. (formerly CardioTech
International) Albis Plastics Ashley Polymers Ashlene .RTM. BASF
Luran .RTM. BASF Ultradur .RTM. Bayer MaterialScience Apec .RTM.
Bayer MaterialScience Bayblend .RTM. Bayer MaterialScience Bayfol
.RTM. Bayer MaterialScience Makroblend .RTM. Bayer MaterialScience
Makrofol .RTM. Bayer MaterialScience Makrolon .RTM. Bayer
MaterialScience Petlon .RTM. Bayer MaterialScience Texin .RTM.
Bayer MaterialScience AG Apec .RTM. Bayer MaterialScience AG
Bayblend .RTM. Bayer MaterialScience AG Makrolon .RTM. CENTROPLAST
Engineering Plastics GMBH CENTROCARB Chase Plastics CP Pryme .RTM.
Cheng Yu Plastic Company Limited (formerly Luen Cheong Hong)
Chengdu Polyster Co. Chi Mei Corporation (ChiMei) Wonderlite .RTM.
Chi Mei Corporation (ChiMei) Wonderloy .RTM. Clariant Clariant
Renol Cool Polymers, Inc. Coolpoly .RTM. Diamond and Network
Polymers Dow Chemical CALIBRE .TM. MEGARAD .TM. Dow Chemical Retain
.RTM. DSM Biomedical Bionate .RTM. DSM Biomedical CarboSil .RTM.
DSM Engineering Plastics Arnite .RTM. DSM Engineering Plastics
Electrafil .RTM. DSM Engineering Plastics Plaslube .RTM. DSM
Engineering Plastics Stapron .RTM. DSM Engineering Plastics Stapron
.RTM. C E-Polymers Co. Ltd. TEKALOY .RTM. E-Polymers Co. Ltd.
TEKANATE .RTM. E-Polymers Co. Ltd. TEKANATE .TM. Eastman Chemical
Eastalloy Ecomass Technologies Engineered Plastics Corporation
Ensinger Hydel .RTM. Ensinger Tecanat .TM. Entec Engineered Resins
Hybrid .RTM. Entec Engineered Resins Hylex .RTM. Entec Engineered
Resins Hysun .TM. EPICHEM srl Epiblend EPICHEM srl Epicarb EPICHEM
srl Epilon EPMG, Inc. Erhard Hippe KG Eurotec Tecodur .RTM. Evonik
Corporation Europlex .RTM. Evonik CYRO CYREX Evonik CYRO Cyrex
.RTM. Evonik CYRO Cyrolon .RTM. GEHR Plastics Inc Gichem srl
GIBLEND Gichem srl GILON Global Polymers Corporation Isoflon
Kazanorgsintez Kingfa Sci. & Tech. Co. Kingfa Sci. & Tech.
Co. LONOY Kleerdex Company Elson .RTM. Kostat Kostat ICP-STAT Kotec
Corp Carbotex LATI LASTILAC LATI LATILON LATI LATILUB LATI
LATISHIELD LATI LATISTAT Lehmann & Voss & Co. ELECTRAFIL
Lehmann & Voss & Co. LUVOCOM .RTM. Lehmann & Voss &
Co. PLASLUBE LG Chemical LUPOY LNP CYCOLOY .RTM. LNP Faradex LNP
Lexan .RTM. LNP Lubricomp .RTM. LNP Lubriloy .RTM. LNP Stat-Kon
.RTM. LNP Stat-Loy .RTM. LNP Thermocomp .RTM. LNP VALOX .RTM. LNP
Verton .TM. Loxim Industries LTL Color Compounds ColorFast .RTM.
LTL Color Compounds ColorRx .TM. Lucent Polymers M. Holland Company
Mitsubishi lupilon .RTM. Mitsubishi Xantar .RTM. MRC Polymers
NAXALOY .TM. MRC Polymers NAXELL .TM. Nanocyl PLASTICYL .TM.
Network Polymers Nylene .RTM. Naxel .TM. Omni Plastics OmniTech
.TM. Omni Plastics OmniTuff .TM. Omnia Plastica s.p.a. Ovation
Polymers GIENALL Ovation Polymers Nemcon .TM. Ovation Polymers Nima
.TM. Ovation Polymers OpteSTAT .TM. Ovation Polymers RIGITRON
Ovation Polymers TRIZIN Ovation Polymers UTTAP Owens Corning Oxford
Polymers Parker Chomerics Duralan II .TM. Parker Chomerics PREMIER
.TM. Parker Chomerics WIN-SHIELD .TM. Plaskolite Plastomer
Technologies Amicon .TM. PlastxWorld, Inc. CEVIAN .RTM. Polimeri
Europa (Former EniChem) KOBLEND Polykemi AB POLYblend Polykemi AB
POLYlux Polykemi AB SCANBLEND Polykemi AB SCANTEC Polymer Resources
Corporation PolyOne Corporation Edgetek .RTM. PolyOne Corporation
LubriOne .TM. PolyOne Corporation Lubri-Tech .TM. PolyOne
Corporation Stat-Tech .TM. Polyram Polyram RamLloy Polyram RamTough
Premix Thermoplastics Inc. PRE-ELEC .RTM. Prima Plastics PRIMABLEND
Prima Plastics PRIMANATE Proto3000 Quinn Group Quinn Group SPC
RedEye On Demand Reliance Industries SABIC Innovative Plastics (GE
Plastics) Cycolac .RTM. SABIC Innovative Plastics (GE Plastics)
Cycoloy .RTM. SABIC Innovative Plastics (GE Plastics) Geloy SABIC
Innovative Plastics (GE Plastics) Lexan .RTM. SABIC Innovative
Plastics (GE Plastics) LNP Colorcomp SABIC Innovative Plastics (GE
Plastics) LNP Faradex SABIC Innovative Plastics (GE Plastics) LNP
Lubricomp SABIC Innovative Plastics (GE Plastics) LNP Lubriloy
SABIC Innovative Plastics (GE Plastics) LNP Staramide SABIC
Innovative Plastics (GE Plastics) LNP Stat-kon SABIC Innovative
Plastics (GE Plastics) LNP Stat-loy SABIC Innovative Plastics (GE
Plastics) LNP Thermocomp SABIC Innovative Plastics (GE Plastics)
LNP Thermotuf SABIC Innovative Plastics (GE Plastics) LNP Verton
SABIC Innovative Plastics (GE Plastics) Remex SABIC Innovative
Plastics (GE Plastics) SABIC PC SABIC Innovative Plastics (GE
Plastics) Valox .RTM. SABIC Innovative Plastics (GE Plastics) Xenoy
SABIC Innovative Plastics (GE Plastics) Xenoy .RTM. SABIC
Innovative Plastics (GE Plastics) Xylex Samsung, Cheil Industries
Staroy .RTM. Samyang Triloy .RTM. Samyang Trirex .RTM. Shinil
Chemical SHINCON Shinil Chemical SHINFLAME Shinil Chemical SHINSTAT
Shinil Chemical SHINSTRA Shinkong Synthetic Fibers Corp Shinblend
.RTM. Shuman Sibur SO.F.TER Blendfor A .RTM. SO.F.TER Cabofor .RTM.
Spartech Spartech Millennium Spartech Royalite Spartech Sungard
Spartech UltraTuf SPS Guang Zhou POLLITE .TM. SPS Guang Zhou POLLOY
.TM. Star Plastics, Inc Stratasys Styron CALIBRE .TM. Styron EMERGE
.TM. Styron Pulse .RTM. Techmer Lehvoss Compounds (TL Compounds)
Electrafil .RTM. Techmer Lehvoss Compounds (TL Compounds) Luvotech
.TM. Techmer Lehvoss Compounds (TL Compounds) Plaslube .RTM. Teijin
Multilon Teijin Panlite .RTM. Ter Hell Plastic GMBH Terez .RTM. The
Matrixx Group The Plastics Group of America Polifil .RTM. Tipco
Industries Ltd., India Tipcofil .RTM. Tisan Engineering Plastics
TISARBON .RTM. Tisan Engineering Plastics TISBLEND .RTM. Toyobo
VYLOPET .RTM. TP Composites, Inc Elastoblend .RTM. TP Composites,
Inc Electrablend .RTM. TP Composites, Inc HiFill FR .RTM. TP
Composites, Inc HiFill .RTM. TP Composites, Inc Luriblend .RTM. TP
Composites, Inc Plastiblend .RTM. TP Composites, Inc Statiblend
.RTM. Wanshijie Plastic Sheet Co Westlake Plastics Zelux .RTM. Wico
Plast Wicolon Zhejiang Juner New Materials Co.
[0264] FIGS. 13-16 illustrate several embodiments of discs which
may be used according to the instant invention.
[0265] FIG. 13 is a perspective view of one embodiment of a disc.
In this embodiment, the disc 52 has a discus shape of varying
thickness, 1/4'' in the center tapering with a uniform slope to
1/8'' at the circumferential edge. In an imbricated pattern, edges
of adjacent discs will overlap, creating areas of increased
thickness having multiple disc layers. Ordinarily, this pattern
will not overlap the center, or thickest region, of the disc. Thus,
a projectile striking the disc pattern at any point will impact
either a singular disc near its thickest region, or multiple
layered discs at least as thick, and likely thicker, than the
thickest region of the singular disc. Moreover, the slope of the
discus shape between areas of varying thickness discourage any
perpendicular ballistic impact.
[0266] FIG. 14 shows a side view of another embodiment of a disc or
tile. In this embodiment, the disc or tile includes planar faces.
Similar to the disc of FIG. 13, the disc may be a substantially
circular disc, or may have other shapes such as oval, triangular,
square or the like.
[0267] FIG. 15 is a perspective view of a disc of an alternative
embodiment of the invention. In this embodiment, formation of the
disc is substantially as described above in reference to FIG. 13,
varying only in the slope of the end result. While varying in
thickness from the center to the edge, the slope of tapering is not
uniform, leaving a more pronounced bulging center having a domed
shape. This leaves the surface area extending from the
circumference edge to the domed center substantially planar. This
embodiment allows for the discs to have a greater overlapped
surface area, increasing the surface area in which a projectile
would encounter multiple layers of disc. However, the substantially
planar region increases the probability of a perpendicular strike.
The domed discs can be laid out in an analogous manner to that
described above and assembled into body armor capable of defeating
rifle threat levels three to five.
[0268] FIG. 16 is a cross-sectional side view of the alternative
embodiment shown in FIG. 15.
[0269] FIGS. 17A-26C illustrate several embodiments of tiles that
may be used according to the instant invention. Each of the tiles
may be partially or completely encased within any of the previously
discussed containment wraps, e.g. an E-glass/resin wrap, a polymer
wrap and/or a titanium wrap. In on embodiment, each of the tiles
may be laid out in a side-by-side mosaic configuration and not
overlapped to form an armor system. The tiles may have outside
dimensions (e.g. a length and/or width) of anywhere from 1/2 inch
to 6 inches, for example, from about 1 inch to about 3 inches, for
example, 2 inches.
[0270] In other embodiments, the discs or tiles are overlapped in
an imbricated pattern. The overlap of the imbricated placement
pattern has been found to effectively spread the force of a
high-velocity projectile hit to adjacent discs, thereby preventing
penetration and backside deformation. Additionally, because of the
slight tilt of each overlapping disc in the imbricated pattern, a
perpendicular hit is very unlikely and some of the energy will be
absorbed in deflection. In the discus embodiment, the tapering of
thickness, forming a non-planar inclined surface renders a
perpendicular strike extraordinarily unlikely.
[0271] FIG. 27 shows an imbricated pattern of discs 52 (such as
disc 52 illustrated in FIG. 13) coupled to a substrate. The
substrate could be an adhesive impregnated polyethylene or aramid
fiber fabric. Suitable fabrics include the fabric sold under the
trademark SPECTRA.RTM. by AlliedSignal of Morristown, N.J.,
TWARON.RTM. microfiliment by Akzo-Nobel of Blacklawn, Ga., SB31 and
SB2, sold under the trademark DYNEEMA, by DSM of Holland, PBO sold
under the trademark ZYLON.RTM. by Toyobo of Tokyo, Japan (pursuant
to a license from Dow Chemical, Inc. of Midland Mich.), KEVLAR.RTM.
or PROTERA.RTM. by E.I. Dupont de Nemours & Company of
Chattanooga, Tenn. Other suitable fabrics will occur to one of
ordinary skill in the art.
[0272] Some suitable substrates are available with an aggressive
adhesive coating covered by a release paper. In addition to being
aggressive, it is important that the adhesive once cured remains
flexible to reduce separation of the discs and substrate during a
ballistic event and to aid in flexibility. The substrate of a
desired size may be cut and the release paper peeled back to expose
the adhesive surface. The disc can then be laid out directly onto
the adhesive which retains them in position relative to one
another. Because the substrate is flexible and the discs flex about
their intersection, pivoting somewhat within the imbricated layout,
the combined unit is significantly flexible; on the order of 60%
more flexible than the prior art metal plate and coin configuration
armor. Alternatively, the pattern may be laid out and the substrate
adhered over the top.
[0273] The next step is to place another layer of this adhesive
coated flexible substrate on the other side of the discs to secure
them in a flexible position that does not change when the panel is
flexed. The actual position of each disc remains substantially in
the same place it was laid. This second layer of adhesive fabric
used to envelop the imbricated pattern provides further staying
power, thereby reducing the risk that a disc will shift and the
body armor will fail.
[0274] It has been found that the above-disclosed invention will
defeat in a body armor system, rifle level three to five threats,
and all lesser threats. Additional layers of the adhesive coated
flexible substrate material may be added to either side in any
proportion (i.e., it is within the scope and contemplation of the
invention to have more substrate layers on one side of the panel
than the other side of the panel) in multiple layers to achieve
different performance criteria. Some situations benefit from
allowing the discs to move slightly during the ballistic event,
while others make it desirable that the disc remain as secure in
place as possible.
[0275] In an alternative embodiment of the invention, a "dry" high
tensile strength flexible substrate is provided. It is then coated
with a flexible bonding agent, for example, a silicon elastomer
resin. The discs may then be laid out as described above. The
bonding agent is then cured to flexibly retain the relative
locations of the discs. A similarly coated layer can be used to
sandwich the plate from the opposite side. It is also within the
scope and contemplation of the invention to use one layer with a
flexible bonding agent while a facing layer is of the peel and
stick variety described above. As used herein, "adhesive
impregnated substrate" refers to suitable flexible high tensile
strength material having an adhesive disposed on one side, whether
commercially available with adhesive in place or coated later as
described above.
[0276] In yet another embodiment, an adhesive impregnated substrate
is created by either above described method and the (sandwiching)
layer is non-adhesive and merely coupled to the underlying
substrate about the periphery of the panel. This will somewhat
degrade the retention of the disc as compared to sandwiching
between adhesive layers. Accordingly, this configuration will not
survive as many hits and the front layer attached about the
periphery serves primarily as a spall shield.
[0277] FIG. 28 is a frontal view of one embodiment of a body armor
vest within which the previously discussed discs or tiles may be
integrated. Representatively, in one embodiment, the armor is a
suit of body armor. The body armor 10 covers a user's torso and is
designed to protect the vital areas from high-velocity projectiles.
Flaps 20 on the body armor extend around the wearer's body to
extend protection to the wearer's sides. In one embodiment the body
armor wraps around a segment of the wearer, for instance the torso,
providing substantially uniform armor protection in an enveloping
circumference.
[0278] FIG. 29 is a cutaway frontal view of one embodiment of a
suit of body armor. Discs 52 are arrayed in an imbricated pattern
to cover vital areas where the body armor is worn. Unlike the
10''.times.12'' rigid plates of prior art, the imbricated pattern
can flex around body contours and is therefore considerably more
comfortable and also more readily concealable. Each disc 52 is
formed of a high hardness material. In one embodiment, each disc is
discus shaped having a maximum thickness in the center of the disc
and declining in thickness towards the outer edge by providing one
or more downwardly inclined surface segments. In one embodiment,
the thickness of the discus shaped disc declines in a uniform
downward inclined slope from the center towards the outer edge. In
another embodiment the discus shape has an internal circumference
within which the disc is uniformly thick and slopes uniformly
downward between the internal circumference and the circumferential
edge of the disc.
[0279] Typically, the edge thickness will be approximately one-half
the thickness in the center. As such, when laid out in the
imbricated pattern the discs exhibit a pivot capability which
allows on the order of 60% greater flexibility than metal plates or
existing coin arrangements. Many such suitable ceramic materials
exist which are also of relatively lighter weight when compared to
steel or other high hardness metals.
[0280] The tapering design intrinsic to the discus shape of one
embodiment of the invention renders the disc surface non-planar,
providing a slope to deflect ballistic impacts as compared with a
uniform flat planar surface. In this regard, the ceramic composite
material can be sintered and/or molded into a homogenous ballistic
grade discus shape more easily and less expensively than can a
metal disc, which must either be lathed or tooled to produce a
similar tapering discus form. However, discus shaped metal discs
are within the scope and contemplation of the invention. Through
appropriately laying out discs in an imbricated pattern, the
overall body armor 10 remains flexible and also provides good
protection against high velocity projectiles.
[0281] Additionally, the lighter weight and greater flexibility of
the ceramic composite as compared to prior art protection from high
velocity projectiles, allows for greater mobility and range of
motion by the wearer. For instance, body armor vests composed of
imbricated ceramic discs of ballistic grade hardness and fracture
toughness may wrap entirely around a segment of the wearer, for
instance the torso, extending disc protection up to 360 degrees
about the wearer. The lighter ceramic material also avoids
pronounced negative buoyancy of high hardness metal coins, tiles,
or plates typical of prior art body armor. This provides for
climbing or swimming uses in the field for which prior art body
armor is not suitable.
[0282] The imbricated pattern is typically sandwiched between two
layers of fabric 14 made of high tensile strength fibers, such as
aramid fibers or polyethylene fibers. The fabric 14 should be tear
and cut resistant and is preferably ballistic grade material
designed to reduce fragmentation. This fabric 14 can be adhesive
impregnated, thus, the adhesive on the fabric adheres to the discs
that compose the imbricated pattern and retains their relative
position. One or more additional layers of the fabric 14 may be
added to the sandwich. This will be discussed further below.
[0283] Underlying the imbricated pattern of discs 52 that is
sandwiched between two or more layers of tear and cut resistant
fabric layers 14 is conventional soft body armor 16. A
high-velocity projectile is deemed defeated even if it penetrates
the discs of the imbricated pattern and all fabric layers if it
does not penetrate the underlying soft body armor or cause backside
deformation of greater than 1.73'', as backside deformation is
defined by the National Institute of Justice (NIJ). In one
embodiment, multiple layers of fabric are added to the side between
the ceramic discs and the wearer as additional protection against
backside deformation and to catch projectiles and fragments
thereof. Attachment straps, such as strap 18, connect the armor to
a body segment, for instance the shoulders, to provide additional
support. Attachment strap 18 could be any conventional strapping
common in the industry.
[0284] To arrange the imbricated pattern, the discs are laid out
from left to right. Each subsequent row is also laid out left to
right. It has been found that switching from left to right, then to
right to left, creates weakness in the resulting pattern that often
causes failure. Discs within each row form a substantially straight
horizontal line. Because the discs overlap, each disc lies on a
slight tilting slope relative to a line normal to the horizontal
layout surface. In one embodiment, this slight slope of the discs
complements their inclined discus shape to increase the probability
of impact deflection.
[0285] After the discs are laid out from left to right and top to
bottom and sandwiched between a pair of adhesive layers, the entire
pattern is inverted for assembly into body armor. It has been found
that the majority of threats arrive at a downward trajectory. Thus
it is desirable that each row of discs overlap the row below it as
the armor is worn. It is, however, within the scope and
contemplation of the invention to lay out the discs in an
alternative order, e.g., right to left, bottom to top. It is also
contemplated that inverting the imbricated pattern in the course of
assembling the body armor may be connected such that each row
overlaps the row above it.
[0286] In one embodiment, suitable ceramic composites for the discs
or tiles would have relatively high hardness and fracture
toughness. Typically, such materials would have at least
approximately 12 GPa in hardness and at least 3.5 MPa m.sup.1/2 in
fracture toughness in order for the armor to withstand a level
three ballistic event as defined by the National Institute of
Justice (NIJ). A level three threat is a full metal jacket
7.62.times.51 mm 150 grain round traveling at 2700-2800 ft./sec.
Ultimately, hardness and fracture toughness levels will depend on
the type of ceramic composite employed. For exemplary embodiments
of the present invention using alumina bases, the fracture
toughness minimum for alumina would be 3.8 MPa m.sup.1/2 and 4.5
MPa m.sup.1/2 for zirconia toughened alumina. The hardness for
alumina would be in the approximate range of 12 to 15 GPa, and for
zirconia toughened alumina, the hardness would be at least
approximately 15 GPa.
[0287] The ceramics are mixed in ways commonly known in the art.
Sintering and molding, including injection molding, methods to form
the disc are well known in the art. In one embodiment, the discs
may be formed by injection molding and then pressing to the desired
shape. Once formed, certain embodiments of the discs are then
encompassed with a containment wrap material. This material
provides greater integrity to the disc and increases its fracture
toughness, consequently enhancing its ability to absorb the impact
of ballistic projectiles without disassociation. In one embodiment,
this wrap is a glass fiber wrap adhered by an adhesive substrate.
Suitable glass fiber materials include E-glass and S-2 Glass
available from Owens Corning Fiberglas Technology, Inc. of Summit,
Ill. Suitable adhesives include modified epoxy resins. The
containment wrap and epoxy resin substrate can be applied to the
disc by autoclaving, or in other ways known to the art. Strength,
cohesion and structural integrity may also be imparted by
overlaying the disc surface with aramid fibers, layered or
cross-laid on an adhesive substrate.
[0288] Typically, disc 52 has a radius between 1/2'' and 3''.
Longer radii reduce flexibility but also manufacturing cost. In a
current embodiments, a 1'' or 2'' radius is employed. Each disc
tapers in thickness varying between its center region (where the
thickness is at its maximum) and its edge (where the thickness is
at a minimum). Maximum and minimum thicknesses will vary according
to the level of ballistic threat to be defeated. For instance, to
defeat a high velocity armor piercing or armor piercing incendiary
ballistic rifle threat, a maximum thickness of 3/8'' in the center
tapering to 3/20'' minimum thickness at the edge may be used. A low
velocity rifle threat (or a high velocity pistol threat) may only
require a thickness of between 1/8'' (maximum) and 1/10''
(minimum). In one embodiment, the discus shaped discs have a center
thickness of approximately 1/4'' and an edge thickness of
1/8''.
[0289] FIG. 30-FIG. 35 illustrates further embodiments of possible
patterns within which the discs or tiles may be arranged.
[0290] In particular, FIG. 30 illustrates one embodiment of a
mosaic side-by-side tile configuration. In this embodiment, the
tiles are hexagonal tiles. The mosaic pattern may be formed by
arranging tiles in a single row in a side-by-side configuration in
which each tile is laid next to the other but without overlapping
the other. Each row is then arranged next to another row such that
tiles in each row abut tiles of an adjacent row. The tiles
illustrated in FIG. 30 may be flat or have a non-planar surface on
either side.
[0291] FIG. 31 illustrates one embodiment of an imbricated tile
configuration. In this embodiment, the tiles are arranged in rows
which overlap tiles of adjacent rows. The tiles may be hexagonal
tiles with flat or non-planar surfaces.
[0292] FIG. 32 illustrates one embodiment of an imbricated
overlapping disc pattern. The discs may be substantially similar to
those described in reference to FIG. 13.
[0293] FIG. 33 illustrates one embodiment of an imbricated tile
pattern using multi-thickness tiles such as that described in
reference to FIG. 15 and FIG. 16.
[0294] FIG. 34 illustrates one embodiment of an imbricated tile
pattern. More specifically, a single row imbricated overlapped tile
configuration is shown. In this embodiment, the tiles may be
octagonal shaped armor tiles having a flat or non-planar
surface.
[0295] FIG. 35 illustrates one embodiment of a multi-thickness
diamond shaped tile similar to the multi-thickness round tile
illustrated in FIG. 15 and FIG. 16. The multi-thickness perimeter
shapes of the tiles are shown as diamond shaped but can also be
rectangular, square, octagonal, hexagonal, etc.
[0296] FIG. 36 illustrates a perspective view of one embodiment of
a tile. In one embodiment, the tile is a multi-thickness diamond
shaped tile such as those shown laid out in FIG. 35. The tile is
considered a multi-thickness tile because it is thicker at a center
portion than the perimeter portion.
[0297] FIG. 37 illustrates a top plan view of one embodiment of a
tile. The tile may be a multi-thickness diamond shaped tile such as
that illustrated in FIG. 36. From this view, the shape of the tile
can be more clearly seen.
[0298] FIG. 38 illustrates one embodiment of an imbricated tile
pattern. The imbricated tile pattern may be formed by a plurality
of diamond shaped multi-thickness tiles such as those illustrated
in FIGS. 36 and 37. As can be seen from this view, the thinner
perimeter regions of each of the tiles overlap.
[0299] FIG. 39 illustrates one embodiment of an imbricated tile
pattern. The imbricated tile pattern may be formed by a plurality
of diamond shaped multi-thickness tiles such as those illustrated
in FIGS. 36 and 37. As can be seen from this view, the thinner
perimeter regions of each of the tiles overlap.
[0300] It should also be appreciated that reference throughout this
specification to "one embodiment", "an embodiment", or "one or more
embodiments", for example, means that a particular feature may be
included in the practice of the invention. Similarly, it should be
appreciated that in the description various features are sometimes
grouped together in a single embodiment, Figure, or description
thereof for the purpose of streamlining the disclosure and aiding
in the understanding of various inventive aspects. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that the invention requires more features than are
expressly recited in each claim. Rather, as the following claims
reflect, inventive aspects may lie in less than all features of a
single disclosed embodiment. Thus, the claims following the
Detailed Description are hereby expressly incorporated into this
Detailed Description, with each claim standing on its own as a
separate embodiment of the invention.
[0301] In the foregoing specification, the invention has been
described with reference to specific embodiments thereof. It will,
however, be evident that various modifications and changes can be
made thereto without departing from the broader spirit and scope of
the invention as set forth in the appended claims. The
specification and drawings are, accordingly, to be regarded in an
illustrative rather than a restrictive sense.
* * * * *