U.S. patent application number 15/879995 was filed with the patent office on 2018-08-16 for ballistic composite panels with differing densities.
The applicant listed for this patent is ROCKY RESEARCH. Invention is credited to Kaveh Khalili, Uwe Rockenfeller.
Application Number | 20180231355 15/879995 |
Document ID | / |
Family ID | 57882470 |
Filed Date | 2018-08-16 |
United States Patent
Application |
20180231355 |
Kind Code |
A1 |
Rockenfeller; Uwe ; et
al. |
August 16, 2018 |
BALLISTIC COMPOSITE PANELS WITH DIFFERING DENSITIES
Abstract
A multi-paneled penetration resistant composite comprises a
layered panel configuration that mitigates transmission of impact
stress. For example, areas of varying density within a multi-layer
panel are configured to can mitigate transmission of stress between
adjacent, or proximate, composite layers within a panel.
Inventors: |
Rockenfeller; Uwe; (Boulder
City, NV) ; Khalili; Kaveh; (Boulder City,
NV) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROCKY RESEARCH |
Boulder City |
NV |
US |
|
|
Family ID: |
57882470 |
Appl. No.: |
15/879995 |
Filed: |
January 25, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14810309 |
Jul 27, 2015 |
|
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15879995 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41H 5/0485
20130101 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
1. A multilayer composite ballistic panel having regions of
differing densities, comprising: a first region of at least one
first layer of woven fabric material comprising metal salt, oxide,
hydroxide or hydride polar bonded onto the at least one first layer
of material, the first region having a first density; a second
region of at least one second layer of woven fabric material
comprising metal salt, oxide, hydroxide or hydride polar bonded
onto the at least one second layer of woven fabric material, the
second region having a second density; and a third region of at
least one third layer of woven fabric material having a third
density and comprising metal salt, oxide, hydroxide or hydride
polar bonded onto the at least one third layer of woven fabric
material, the third region having a third density, wherein the at
least one second layer is disposed between the at least one first
layer and the at least one third layer, wherein the second region
of the at least one second layer is configured to mitigate stress
propagation into the third layer caused by deformation of the at
least one first layer, wherein the second density is less than the
first and third densities for mitigating the stress
propagation.
2. The multilayer composite ballistic panel of claim 1, wherein the
first density is greater than the third density.
3. The multilayer composite ballistic panel of claim 2, wherein the
first density is at least 10% greater than the second or third
densities.
4. The multilayer composite ballistic panel of claim 1, wherein the
first density is less than the third density.
5. The multilayer composite ballistic panel of claim 1, further
comprising at least one fourth region of at least one fourth layer
of woven fabric material having a fourth density and comprising
metal salt, oxide, hydroxide or hydride polar bonded onto the at
least one fourth layer of woven fabric material.
6. The multilayer composite ballistic panel of claim 1, wherein the
first region has a different density of bonded metal salt, oxide,
hydroxide or hydride than the second region.
7. The multilayer composite ballistic panel of claim 1, wherein the
first region has a greater density of bonded metal salt, oxide,
hydroxide or hydride than the second region.
8. The multilayer composite ballistic panel of claim 1, wherein the
first region has a different metal salt, oxide, hydroxide or
hydride compound bound to the woven fabric material than the second
region.
9. The multilayer composite ballistic panel of claim 8, wherein the
third region has a different metal salt, oxide, hydroxide or
hydride compound bound to the woven fabric material than the second
region.
10. The multilayer composite ballistic panel of claim 1, wherein
the first region has a different woven fabric material than the
second region.
11. The multi-panel ballistic composite article of claim 10,
wherein the first region has a different S-2 glass, polyamide,
polyphenylene sulfide, polyethylene, high modulus polyethylene,
carbon or graphite woven fabric material than the second
region.
12. The multilayer composite ballistic panel of claim 1, wherein
the third region has a different woven fabric material than the
second region.
13. The multi-panel ballistic composite article of claim 12,
wherein the third region has a different S-2 glass, polyamide,
polyphenylene sulfide, polyethylene, high modulus polyethylene,
carbon or graphite woven fabric material than the second
region.
14. The multilayer composite ballistic panel of claim 1, wherein
the at least one first layer of woven fabric and the at least one
second layer of woven fabric have a different weave pattern.
15. The multilayer composite ballistic panel of claim 1, wherein
the at least one first layer of woven fabric has a first filament
diameter and the at least one second layer of woven fabric has a
second filament diameter, and the first and second filament
diameters are different.
16. The multilayer composite ballistic panel of claim 1, wherein at
least one first layer of woven fabric material has a first loading
density of metal salt, oxide, hydroxide or hydride polar bonded
onto the at least one first layer of material and the at least one
second layer of woven fabric material has a second loading density
of metal salt, oxide, hydroxide or hydride polar bonded onto the at
least one second layer of material, and the first and second
loading densities are different.
17. The multilayer composite ballistic panel of claim 16, wherein
at least one third layer of woven fabric material has a third
loading density of metal salt, oxide, hydroxide or hydride polar
bonded onto the at least one third layer of material and the first,
second and third loading densities are different.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/810,309, filed on Jul. 27, 2015, entitled "BALLISTIC
COMPOSITE PANELS WITH DIFFERING DENSITIES," the entirety of which
is hereby incorporated by reference.
TECHNICAL FIELD
[0002] Aspects relate to multilayer composite panels that are
resistant to ballistic penetration, or configured to reduce the
speed of a ballistic projectile. In some aspects, an anti-ballistic
article includes one or two panels of woven ballistic layers,
wherein the woven ballistic layers are arranged in a configuration
of varying density in order to mitigate stress propagation between
adjacent layers upon projectile impact.
BACKGROUND
[0003] Many different uses have been found for penetration
resistant materials. For example, penetration resistant materials
can be used to protect storage containers, vehicles and personnel
from damage by projectiles. These materials also generally protect
from penetration from flying shrapnel and the like.
[0004] Many types of penetration resistant materials, such as
Kevlar.RTM., are made from high strength fibers. These fibers can
be integrated with, or layered into, articles of clothing such as
vests or parts of vests. In addition, the fibers can be used as
part of a woven or knitted fabric. For other applications, the
fibers are encapsulated or embedded in a composite material.
[0005] Because there is a trade-off in weight versus ballistic
penetration resistance, many materials of a specified weight are
unable to stop, or greatly slow down, a ballistic projectile.
Moreover, it is known that stacking multiple layers of
anti-ballistic composites generally increases resistance to
ballistic penetration. However the multiple layers also result in
an increase in overall weight of the completed panels. The overall
weight of the panels becomes increasingly important for panels that
are used, for example, on anti-ballistic armor that is wearable.
Weight can also be an important factor for large vehicles, such as
trucks, ships or aircraft because additional weight reduces fuel
efficiency and speed.
SUMMARY
[0006] Aspects of the invention relate to the discovery of a
non-linear relationship between the number of stacked panels within
a penetration resistant material and the reduction of a
projectile's velocity as it travels thought the anti-ballistic
article. While not being limited by any particular theory, it is
believed that as a projectile passes through one or more layers of
material in a multilayer panel, its force may result in stress
propagation that may "pre-stress" subsequent panels within the
ballistic article. This pre-stress force on the subsequent panels
may reduce the ability of adjacent interior panels to slow the
ballistic projectiles as compared to exterior panels. For example,
when a ballistic projectile contacts a first outer panel, it may
deform one or more layers in that panel. That deformation may
result in a shock wave, or pieces of the first panel, impacting or
cracking and weakening the adjacent layer (or layers) in the
adjacent panel. This pre-stress on the layers of adjacent panels
may result in the adjacent panel being unable to provide its full
potential of ballistic protection.
[0007] This may be particularly true for multilayer composite
panels, wherein the interlocking of crystals between adjacent
layers of composite material may reduce the ductility of each
layer. Thus, deformation of a first layer results more easily in
pre-stress of adjacent layers of the panel. Accordingly, if one
ballistic composite panel alone provides a reduction of x feet per
second (ft/s) to the entrance velocity of an impacting projectile,
two adjacent panels may provide a reduction of less than
2.times.ft/s.
[0008] In some cases, large projectiles can be traveling at impact
velocities greater than 8,000 ft/s. While it may not be feasible to
completely stop such projectiles, in some embodiments it is only
necessary to slow the velocity below a pre-determined threshold.
This velocity reduction can reduce the damage, and potential for
explosions, of the equipment being protected by the anti-ballistic
materials. For example, some embodiments relate to impact resistant
cargo containers for missiles, other energetic materials, or other
weaponry. While anti-ballistic containers using embodiments of
anti-ballistic articles described herein may not be able to
completely prevent a ballistic projectile from piercing the outer
shell of the container, the articles may be able to reduce the
speed of the projectile below the threshold that would cause an
explosion of the weaponry upon impact. As discussed above, there is
a relationship between the weight of the panels within an
anti-ballistic article and the ability of the panels to prevent
penetration. In some embodiments it may be more desirable to have a
reduced weight container that only slows certain ballistic
projectiles to below a predetermined threshold. In other
embodiments, the container may be designed to be heavier, but have
a sufficient number and/or configuration of panels to prevent
penetration of ballistic projectiles into the interior of the
container.
[0009] Due, in part, to the non-linear relationship between the
number of composite panels in the anti-ballistic article and the
projectile velocity reduction capabilities of each panel, as well
as the number of panels in the anti-ballistic article and the
projectile velocity reduction capabilities of the article,
achieving the needed velocity reduction while satisfying weight
restrictions on anti-ballistic armor can be very difficult. In
order to address the above-described issues, embodiments of the
invention relate to a multi-paneled penetration resistant article
having a panel configuration and/or intra-panel layer configuration
that mitigates transmission of impact stress between adjacent, or
proximate, penetration resistant composite panels. For example,
areas of reduced density, provided by one or both of an
intermediate stress mitigation region or panel positioned between
adjacent composite panels and varying densities of composite layers
within a composite panel, can mitigate transmission of stress
between adjacent, or proximate, composite panels.
[0010] In one embodiment, an intermediate layer can be positioned
between two penetration resistant composite layers to mitigate or
eliminate propagation of stress from a first impact layer to a
second impacted layer. Thus, the stack of the two penetration
resistant composite layers and intermediate layer can provide for
increased resistance to impacting projectiles compared to a stack
of two penetration resistant composite layers placed directly
adjacent to one another. In some implementations, such a
configuration approaches a linear relationship between number of
penetration resistant composite layers and projectile velocity
reduction capability.
[0011] In some embodiments comprising a number of penetration
resistant composite layers, one or more intermediate layers can be
provided between each pair of adjacent composite layers. Some
embodiments can further be provided with one or more hardened
layers that may reduce deformation of impacted composite layers
and/or stop, rather than merely slow down, an incoming projectile.
The intermediate layer(s) may absorb, redirect, or otherwise
mitigate impact stress so as to isolate stress to a single
composite panel or to two proximate composite panels.
[0012] The penetration resistant composites described herein
comprise a substrate material comprised of woven, layered or
intertwined polarized strands of glass, polyamide, polyethylene,
highly modulus polyethylene, polyphenylene sulfide, carbon or
graphite fibers on which a selected metal, salt, oxide, hydroxide
or metal hydride is polar bonded on the surface of the fibers
and/or strands at concentrations sufficient to form bridges of the
salt, oxide, hydroxide or hydrides between adjacent substrate
strands and/or substrate fibers. The salt may be a halide in some
embodiments. Single or multiple layers of the salt or hydride
bonded fibers are coated with a substantially water impermeable
coating material. Panels or other shaped penetration resistant
products may be produced using composite layers.
[0013] The intermediate layer can be, in various implementations, a
compressible material, a ductile material, a spacing matrix, a gap
filled with gas or liquid, a brittle material configured to shatter
at projectile impact speeds, or another material configured to
redirect stress or force away from (for example, perpendicularly
to) the direction of projectile travel. The intermediate layer
material can be selected to be both stress-isolating and
lightweight in some implementations in which the anti-ballistic
article has weight constraints.
[0014] Accordingly, one aspect relates to a multilayer composite
ballistic panel having regions of differing densities, comprising a
first region of at least one first layer of woven fabric material
having a first density and comprising metal salt, oxide, hydroxide
or hydride polar bonded onto the at least one first layer of
material; a second region of at least one second layer of woven
fabric material having a second density and comprising metal salt,
oxide, hydroxide or hydride polar bonded onto the at least one
second layer of woven fabric material; and a third region of at
least one third layer of woven fabric material having a third
density and comprising metal salt, oxide, hydroxide or hydride
polar bonded onto the at least one third layer of woven fabric
material, wherein the first, second and third regions have
different densities.
[0015] In some embodiments, the first density is greater than the
second or third densities. The first density can be at least 10%
greater than the second or third densities. The first density can
be greater than the second density, but less than the third
density. In some embodiments, the first density is less than the
second density.
[0016] Some embodiments further comprise at least one fourth region
of at least one fourth layer of woven fabric material having a
fourth density and comprising metal salt, oxide, hydroxide or
hydride polar bonded onto the at least one fourth layer of woven
fabric material.
[0017] In some embodiments, the first region has a different
density of bonded metal salt, oxide, hydroxide or hydride than the
second region. The first region can have a greater density of
bonded metal salt, oxide, hydroxide or hydride than the second
region. The first region can have a different metal salt, oxide,
hydroxide or hydride compound bound to the woven fabric material
than the second region, and in some embodiments the third region
can also have a different metal salt, oxide, hydroxide or hydride
compound bound to the woven fabric material than the second
region.
[0018] In some embodiments, the first region has a different woven
fabric material than the second region. The first region can have a
different S-2 glass, polyamide, polyphenylene sulfide,
polyethylene, high modulus polyethylene, carbon or graphite woven
fabric material than the second region. The third region can have a
different woven fabric material than the second region. For
example, the third region can have a different S-2 glass,
polyamide, polyphenylene sulfide, polyethylene, high modulus
polyethylene, carbon or graphite woven fabric material than the
second region.
[0019] In some embodiments, the at least one first layer of woven
fabric and the at least one second layer of woven fabric have a
different weave pattern. The at least one first layer of woven
fabric can have a first filament diameter and the at least one
second layer of woven fabric has a second filament diameter, and
the first and second filament diameters are different.
[0020] In some embodiments, at least one first layer of woven
fabric material has a first loading density of metal salt, oxide,
hydroxide or hydride polar bonded onto the at least one first layer
of material and the at least one second layer of woven fabric
material has a second loading density of metal salt, oxide,
hydroxide or hydride polar bonded onto the at least one second
layer of material, and the first and second loading densities are
different. For example, at least one third layer of woven fabric
material can have a third loading density of metal salt, oxide,
hydroxide or hydride polar bonded onto the at least one third layer
of material and the first, second and third loading densities are
different.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The disclosed aspects will hereinafter be described in
conjunction with the appended drawings, provided to illustrate and
not to limit the disclosed aspects, wherein like designations
denote like elements.
[0022] FIG. 1A illustrates an example of a projectile-resistant
enclosure having walls comprising the penetration resistant
composite articles described herein.
[0023] FIG. 1B illustrates a cross-sectional view of one embodiment
of the walls of the enclosure of FIG. 1A.
[0024] FIG. 2A illustrates a schematic diagram of a cross-section
of one embodiment of a projectile impacting a penetration resistant
composite article with a compressible intermediate panel.
[0025] FIG. 2B illustrates a schematic diagram of a cross-section
of one embodiment of a projectile impacting a penetration resistant
composite article with a force dispersing intermediate panel.
[0026] FIGS. 3A-3C illustrate various embodiments of example panel
configurations for a multilayered penetration resistant composite
stack.
[0027] FIG. 4 illustrates an embodiment of a multi-paneled
composite article having composite panels with layers of varying
density.
DETAILED DESCRIPTION
I. Introduction
[0028] Embodiments of the invention relate to multilayered
penetration resistant articles or structures having a mixed layered
configuration that mitigates transmission of impact stress between
different layers within the article. For example, a multilayered
article may have a stress mitigation region positioned between
first and second penetration resistant layers. Deformation or
stress caused by a projectile impact with the first layer or layers
of the article would be mitigated by the stress mitigation region
so that the projectile's impact on the first layers would not
substantially weaken the second layers. Thus, embodiments include
ballistic panels having a mixed stack of penetration resistant
layers with one or more intermediate stress mitigation regions
within or between the ballistic panels. This can create an article
that more effectively reduces the speed of impacting projectiles,
or prevents the projectile's ability to traverse the penetration
resistant layers, in comparison to articles that do not have stress
mitigation regions.
Interpanel Stress Mitigation
[0029] A ballistic article may include one or more ballistic
panels, with each panel having one or more composite layers having
woven fibers and bonded particles as described herein. Each panel
may include any number of layers of woven fabric. For example, each
panel may have 1-30 layers of woven fabric. Other embodiments may
have 5, 10, 15, 20, 25 or more layers. In one embodiment each panel
has between 5-15 layers of woven material.
[0030] A ballistic article can include any number of panels. For
example, the article may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15 or more panels in some embodiments. As used herein,
a panel is not limited to a planar structure, and the term panel
may encompass both planar structures and non-planar (for example
contoured, cylindrical, round, and edged, etc.) structures.
[0031] In one embodiment, an intermediate stress reduction or
mitigation region is positioned between two adjacent penetration
resistant composite panels to mitigate or eliminate propagation of
stress from a first panel to a second panel. Thus, a stack of two
or more penetration resistant composite panels and stress
mitigation regions can provide for increased resistance to
impacting projectiles compared to a stack of two or more
penetration resistant composite panels placed directly adjacent one
another. In some implementations, such a configuration approaches a
linear relationship between the number of penetration resistant
composite panels and the ability of the article to reduce the
velocity of a projectile traversing the article.
[0032] The stress mitigation region can be a stress mitigation
panel and made of a material selected to be both stress-isolating
and lightweight, particularly in implementations in which the
anti-ballistic article has weight constraints. In some
implementations, a stress mitigation panel comprises a compressible
material and/or ductile material. For example, one suitable
material can be foam, for example open-cell foam/reticulated foam,
and the like. Other suitable materials to be used in a stress
mitigation panel can include porous or low-density solids,
lightweight compressible materials, aramid cloth, polyethylene
cloth, unimpregnated glass fiber cloth, carbon fibers, and the
like. In other implementations, the stress mitigation panel can be
made of a structured frame that provides an air gap between
adjacent composite panels in the article. A spacing grid, matrix,
or lightweight 3D knitted spacing fabric may also be used to in a
stress mitigation panel to mitigate transmission of impact stress
from one protective layer to another within the article. In some
embodiments, the gap between adjacent composite panels can be
filled with gas (for example air) or a liquid to provide mitigation
of impact stress between adjacent panels within the ballistic
article.
[0033] In some embodiments, the stress mitigation region comprises
one or more hardened panels disposed between adjacent composite
panels. The hardened panels may reduce deformation of impacted
composite panels and/or stop, rather than merely slow down, an
incoming ballistic projectile. In this embodiment, the force of the
incoming ballistic projectile may be mitigated when the projectile
contacts the hardened panel. As the projectile strikes the hardened
panel, projectile's force is distributed in a direction
perpendicular to its direction of travel. The intermediate hardened
panel (or panels) may absorb, redirect, or otherwise mitigate
impact stress so as to isolate the stress to a single composite
layer, or to two or more proximate composite layers.
[0034] The hardened panels may be made of a brittle material that
cracks or shatters in response to a projectile impact. This type of
brittle panel may redirect and/or absorb propagation of the
projectile's force as it traverses the article. The hard, brittle
material may also help mitigate deformation of the impacted
composite layers or panel. For example, the hardened panel may be
made of ceramic material, such as boron carbide or silicon carbide.
The hardened panel could also be made from other materials, such as
aluminum oxide, silicates, or mixtures thereof.
[0035] In one embodiment, the hardened panels can be provided on
the outermost surface of a ballistic article, which is first
impacted by a projectile, in order to reduce the effectiveness of
armor-piercing projectiles. Some armor piercing projectiles work by
being formed in the shape of a drill bit and being fired though a
barrel that is configured to rotate the projectile. This results in
the projectile hitting the ballistic material with a rotational
drilling action that helps the projectile cut though the ballistic
material. However, a hardened outer panel on the article, such as a
ceramic panel or hardened outer composite layer of the outer panel,
may chip or break the tip of the armor piercing projectile and
thereby reduce its ability to drill through subsequent layers
and/or panels.
[0036] In other embodiments, the penetration resistant article can
comprise a hardened composite layer on a back surface of a
composite panel (that is, the surface opposite the impact surface).
This may mitigate deformation of the final composite layer of the
article and also spread any residual kinetic force of the
projectile as it is exiting the penetration resistant article.
[0037] The penetration resistant articles described herein can have
a plurality of composite panels in an alternating arrangement with
stress mitigation panels. The composite layers in the plurality of
composite panels can comprise the same substrate and bonded
particles or different substrates and/or bonded particles. The
plurality of composite panels may have equal or varying thicknesses
relative to one another. The multi-paneled penetration resistant
article can include any number of composite panels as needed to
reduce the impact speed of an impacting projectile to a desired
velocity.
Intrapanel Stress Mitigation
[0038] As described in more detail below, each panel of composite
material may be made of a substrate material comprised of woven,
layered or intertwined fibers onto which a selected metal, salt
(often a halide), oxide, hydroxide or metal hydride is polar
bonded. Embodiments also include stress mitigation regions within a
panel, formed by regions of differing composite material densities.
For example, the stress mitigation region may one or more regions
within a panel having composite layers of fabric that have
different densities than other regions within a multilayer
composite panel. In one embodiment, regions within the panel having
a lower composite density may reduce the pre-stress force caused by
an impacting projectile.
[0039] As discussed below, regions within a composite panel may
differ in density by a predetermined amount. One region of the
panel may be 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 50 percent or
more different in density than another region. For example, a
multilayer panel may be built to have the first region of woven
fabric layers contacted by the projectile be of a relatively high
density to slow down the projectile. However, a second region of
fabric layers within the panel may be made at a comparatively lower
density to reduce the pre-stress force the projectile will have on
adjacent regions, or panels, within the overall ballistic article.
As one example, a panel with eight layers of woven fabric may have
a first region of four fabric layers with a relatively high overall
density. The next region of four fabric layers may have a
relatively lower density to provide stress mitigation to other
panels within a ballistic article.
[0040] There are a variety of ways to alter the density of regions
within the composite panels. For example, changing the loading
density of the metal, salt, oxide, hydroxide or metal hydride that
is polar bonded on the surface of the fibers is one way to alter
the density of the final woven fabric layers. Generally, a more
dense composite layer of fibers will be created by using a higher
loading density of complex compounds. As one example, using a
loading density of 0.6 gm/cm will create relatively dense composite
layers, and using a loading density of, for example, 0.2 gm/cm will
create a relatively lower density composite material within the
panel. Thus, higher density composite layers may be created by
using a loading density of 0.8, 0.7, 0.6 or 0.5 gm/cm to load the
woven fibers. Lower density fabric layers may be created by using a
loading density of 0.4, 0.3, 0.2 or 0.1 gm/cm.
[0041] The density of a layers within a multi-layer region of a
panel may also be determined by choosing different woven fabric
materials for each layer or region. In addition, selecting
different metal, salt, oxide, hydroxide or metal hydride
compositions to load onto the various fabric layers may also alter
the density of each layer within the panel. Changes to the density
may also result from using fabrics with different weaves, weave
patterns, or filament geometry of the substrate or the substrate
composition.
[0042] Accordingly, in some embodiments, the composite panels can
have regions of fabric layers produced by loading the woven fabric
in each layer with varying salt loading densities. For example, the
panel may have a first region produced by loading one or more
fabric layers with a loading density of 0.6 g/cc of a metal salt,
oxide, hydroxide or hydride and a second region produced by loading
one or more fabric layers with a lower density of 0.2 g/cc of metal
salt, oxide, hydroxide or hydride. Of course, creating composite
panel regions with other densities is contemplated within the scope
of the invention. Varying implementations can have several
different density regions within a panel, wherein each region has
layers of composite material with a different density. In some
embodiments, a panel may have from two to ten regions of differing
densities, preferably from two to six regions of differing
densities.
[0043] For example, one embodiment may be ballistic article
comprising two composite panels within each wall of the article.
The first panel may have ten fabric layers, wherein the first five
fabric layers were produced with a loading density of 0.6 gm/cm
salt and the second five fabric layers were produced with a loading
density of 0.2 gm/cm salt. The second panel may have 20 layers of
fabric with each pair of layers being at a different density than
their adjacent pair of layers. Thus, the second panel may have 10
layer pairs, with the pairs having been produced with salt at a
loading density of 0.6, 0.5, 0.2, 0.3, 0.6, 0.3, 0.5, 0.6, 0.2, 0.6
gm/cm, respectively.
[0044] Other combinations of composite densities within each panel
are also contemplated within the scope of the invention.
Accordingly, the first panel may have 5, 10, 15, 20 or more
different densities of final composite material within teach panel.
Adjacent the first panel may be a stress mitigation region of
relatively low density, and adjacent the stress mitigation region
may be a second panel of 5, 10, 15 or 20 different fabric
densities. In an alternative embodiment, the first and second
panels are directly adjacent one another, and there is no separate
stress mitigation panel disposed between the two panels of varying
density.
[0045] Another related embodiment is a ballistic article with only
a single panel making up a wall of the article. In this embodiment,
the panel may have 10, 20, 30 or more woven fabric layers. Regions
of one or more woven fabric layers may have different densities and
be configured to provide stress mitigation caused by an incoming
ballistic projectile. As the projectile would enter the single
panel, it may traverse a first region of one or more layers having
a first density, and then traverse a second region of one or more
layers having a relatively lower density. As the ballistic
projectile traverses the second region of one or more layers, the
lower density region may provide a stress reduction by mitigating
the pre-stress force of the projectile on additional layers in the
panel.
[0046] In this single panel embodiment, the panel may have many
different regions, with each region having a different density. The
density in each region may result from producing the composite
layers with different salt loading densities. The different density
in each region may also result from choosing different fabric
material having varying weaves, weave patterns, filament geometry
or substrate composition. For example within a ballistic panel, at
least one first layer of woven fabric may have a first filament
diameter and at least one second layer of woven fabric may have a
second, different, filament diameter. By using different filament
diameters, the layers of material may be created to have differing
densities. Similarly, the different layers within a panel may have
different patterns of fabric weaves, wherein each weave pattern
results in a composite layer with a different density. Different
weave patterns may include plain, twill, satin, basket, Leno or
Mock leno weaves in some embodiments.
[0047] This embodiment of a single panel may be designed to provide
a greater level of impact resistance than a panel with a single
loading density or composition of materials. In some embodiments,
the panel may have alternating layers of greater and lesser
composite densities. In some embodiments, the panel may have
progressive layers of different density regions, wherein a first
region of layers has a relatively high density, followed by several
regions of layers with gradually reducing densities, followed by
several regions of layers having gradually increasing
densities.
[0048] It should be realized that the different fabric layers
within a panel can, in some embodiments, have different
compositions of compounds bound to the fibers. For example, one
region within the panel may be made of fabric layers with bonded
metal salt. Another region may have a different metal salt or a
metal oxide bound to the fiber layers. Other regions may have
fibers that were loaded with yet another metal salt or a hydroxide
or metal hydride compounds. This allows one set of layers to be
different in composition from other layers and these differing
compositions may be selected to provide different densities within
a multilayer ballistic panel.
[0049] Some embodiments may combine the intermediate stress
mitigation regions with the varying density of composite layers
within composite panels, for example in order to reduce the needed
thickness of the stress mitigation panel to prevent stress
propagation between adjacent panels, or to increase the
anti-ballistic effectiveness of the overall article.
[0050] It should also be realized that articles within the scope of
the invention may have stress mitigation regions formed within a
panel, and also have stress mitigation regions disposed between
different panels.
II. Overview of Example Penetration Resistant Composites
[0051] The penetration resistant layers and composite products
described herein can be fabricated from a substrate material
comprising woven or intertwined polarized strands or layered
strands of the substrate. Such woven or intertwined substrate
material incorporate or utilize elongated or continuous fibers such
as fabrics or cloth or unwoven intertwined fiber materials such as
yarn, rope or the like where the fibers or strands of fibers have
been twisted or formed in a coherent form such as yarn or weaves of
strands. Various or different weaving patterns may be used,
preferably three-dimensional weaves which yield multi-directional
strength characteristics as compared to two-dimensional weaves
having anisotropic strength characteristics. Moreover, the
substrate utilizes elongated and/or continuous fibers or filaments
as opposed to chopped or loose fibers or strands in which there is
no interlocking or structural pattern to the fibrous substrate.
Suitable materials also include needle woven layers of substrate
fiber strands. Alternatively, layers of elongated, substantially
continuous fiber strands which have not been woven in a
three-dimensional weave may be used. Successive layers of the
fibers are preferably positioned along different axes so as to give
the substrate strength in multiple directions. Moreover, such
layers of non-woven fibers can be positioned between layers of
woven fibers.
[0052] The substrate material of which the fiber strands are made
include glass, polyamide, polyethylene, high modulus polyethylene,
polyphenylene sulfide, carbon or graphite fibers. Glass fibers are
a preferred fiber material, woven glass fibers being relatively
inexpensive and woven glass fiber fabric easy to handle and process
in preparing the composites. The glass fibers may be E-glass and/or
S-glass, the latter having a higher tensile strength. Glass fiber
fabrics are also available in many different weaving patterns which
also makes the glass fiber material a good candidate for the
composites. Carbon and/or graphite fiber strands may also be used.
Polyamide materials or nylon polymer fiber strands are also useful,
having good mechanical properties. Aromatic polyamide resins
(aramid resin fiber strands, commercially available as Kevlar.RTM.
and Nomex.RTM.) are also useful. Yet another useful fiber strand
material is made of polyethylene, polyphenylene sulfide,
commercially available as Ryton.RTM. , or high modulus
polyethylene, commercially available as Spectra.RTM. (Honeywell
International, Morris Township, N.J.). Combinations of two or more
of the aforesaid materials may be used in making up the substrate,
with specific layered material selected to take advantage of the
unique properties of each of them. The substrate material,
preferably has an open volume of at least about 30%, and more
preferably 50% or more, up to about 90%.
[0053] The surface of the fibers and fiber strands of the aforesaid
substrate material may be polarized. Polarized fibers are commonly
present on commercially available fabrics, weaves or other
aforesaid forms of the substrate. If not, the substrate may be
treated to polarize the fiber and strand surfaces. The surface
polarization requirements of the fiber, whether provided on the
substrate by a manufacturer, or whether the fibers are treated for
polarization, should be sufficient to achieve a loading density of
the salt on the fiber of at least about 0.3 grams per cc of open
substrate volume in one embodiment, whereby the bonded metal salt
bridges adjacent fiber and/or adjacent strands of the substrate.
Polarity of the substrate material may be readily determined by
immersing or otherwise treating the substrate with a solution of
the salt, drying the material and determining the weight of the
salt polar bonded to the substrate. Alternatively, polar bonding
may be determined by optically examining a sample of the dried
substrate material and observing the extent of salt bridging of
adjacent fiber and/or strand surfaces. Even prior to such salt
bonding determination, the substrate may be examined to see if oil
or lubricant is present on the surface. Oil coated material may in
some circumstances substantially negatively affect the ability of
the substrate fiber surfaces to form an ionic, polar bond with a
metal salt or hydride. If surface oil is present, the substrate may
be readily treated, for example, by heating the material to
sufficient temperatures to burn off or evaporate the undesirable
lubricant. Oil or lubricant may also be removed by treating the
substrate with a solvent, and thereafter suitably drying the
material to remove the solvent and dissolved lubricant. Substrates
may also be treated with polarizing liquids such as water, alcohol,
inorganic acids, e.g., sulfuric acid.
[0054] The substrate may be electrostatically charged by exposing
the material to an electrical discharge or "corona" to improve
surface polarity. Such treatment causes oxygen molecules within the
discharge area to bond to the ends of molecules in the substrate
material resulting in a chemically activated polar bonding surface.
Again, the substrate material should be substantially free of oil
prior to the electrostatic treatment in some embodiments.
[0055] In one embodiment, one or more particles comprising metal
salt, metal oxide, hydroxide or metal hydride, is bonded to the
surface of the polarized substrate material by impregnating,
soaking, spraying, flowing, immersing or otherwise effectively
exposing the substrate surface to the metal salt, oxide, hydroxide
or hydride. A preferred method of bonding the salt to the substrate
is by impregnating, soaking, or spraying the material with a liquid
solution, slurry or suspension or mixture containing the metal
salt, oxide, hydroxide or hydride followed by removing the solvent
or carrier by drying, heating and/or by applying a vacuum. The
substrate may also be impregnated by pumping a salt suspension,
slurry or solution or liquid-salt mixture into and through the
material. Where the liquid carrier is a solvent for the salt, it
may be preferred to use a saturated salt solution for impregnating
the substrate. However, for some cases, lower concentrations of
salt may be used, for example, where necessitated or dictated to
meet permissible loading densities. Where solubility of the salt in
the liquid carrier is not practical or possible, substantially
homogeneous dispersions may be used. Where an electrostatically
charged substrate is used, the salt may be bonded by blowing or
dusting the material with dry salt or hydride particle.
[0056] As previously described, in some embodiments, it may be
necessary to bond a sufficient amount of metal salt, halide, oxide,
hydroxide or hydride on the substrate to achieve substantial
bridging of the salt, oxide, hydroxide or hydride crystal structure
between adjacent fibers and/or strands. A sufficient amount of
metal salt, oxide, hydroxide or hydride is provided by at least
about 0.3 grams per cc of open substrate volume, preferably at
least about 0.4 grams per cc, and most preferably at least about
0.5 grams per cc of open substrate volume for substrates made of
glass, aramid or carbon and often less for polyethylene based
weaves (for example 0.2 grams/cc to 0.3 grams/cc), which is between
about 25% and about 95% of the untreated substrate volume, and
preferably between about 50% and about 90% of the untreated
substrate volume for most materials except some of the fine
polyethylene based weaves. Following the aforesaid treatment, the
material is dried in equipment and under conditions to form a flat
layer, or other desired size and shape using a mold or form. A
dried substrate will readily hold its shape. In one embodiment, the
substrate is dried to substantially eliminate the solvent, carrier
fluid or other liquid, although small amounts of fluid, for
example, up to 1-2% of solvent, can be tolerated without detriment
to the strength of the material. Drying and handling techniques for
such solvent removal will be understood by those skilled in the
art.
[0057] The metal salts (mostly halides), oxides or hydroxides
bonded to the substrate are alkali metal, alkaline earth metal,
transition metal, zinc, cadmium, tin, aluminum, double metal salts
of the aforesaid metals, and/or mixtures of two or more of the
metal salts. The salts of the aforesaid metals may be halide,
nitrite, nitrate, oxalate, perchlorate, sulfate or sulfite. The
preferred salts may include halides, and preferred metals may
include strontium, magnesium, manganese, iron, cobalt, calcium,
barium and lithium. The aforesaid preferred metal salts provide
molecular weight/electrovalent (ionic) bond ratios of between about
40 to about 250. Hydrides of the aforesaid metals may also be
useful, examples of which are disclosed in U.S. Pat. Nos. 4,523,635
and 4,623,018, incorporated herein by reference in their
entirety.
[0058] Following the drying step or where the salts are bonded to
dry, electrostatically charged substrate, if not previously sized,
the material is cut to form layers of a desired size and/or shape,
and each layer of metal salt or hydride bonded substrate material
or multiple layers thereof are sealed by coating with a
substantially water-impermeable composition. The coating step
should be carried out under conditions or within a time so as to
substantially seal the composite thereby preventing the metal salt
or hydride from becoming hydrated via moisture, steam, ambient air,
or the like, which may cause deterioration of strength of the
material. The timing and conditions by which the coating is carried
out will depend somewhat on the specific salt bonded on the
substrate. For example, calcium halides, and particularly calcium
chloride and calcium bromide will rapidly absorb water when exposed
to atmospheric conditions causing liquefaction of the salt and/or
loss of the salt bond and structural integrity of the product.
Substantially water-impermeable coating compositions include epoxy
resin, phenolic resin, neoprene, vinyl polymers such as PBC, PBC
vinyl acetate or vinyl butyral copolymers, fluoroplastics such as
polychlorotrifluoroethylene, polytetrafluoroethylene, FEP
fluoroplastics, polyvinylidene fluoride, chlorinated rubber, and
metal films including aluminum and zinc coatings. The aforesaid
list is by way of example, and is not intended to be exhaustive.
Again, the coating may be applied to individual layers of
substrate, and/or to a plurality of layers or to the outer, exposed
surfaces of a plurality or stack of substrate layers.
[0059] Panels or other forms and geometries such as concave, convex
or round shapes of the aforesaid coated substrate composites such
as laminates are formed to the desired thickness, depending on the
intended ballistic protection desired, in combination with the
aforesaid composites to further achieve desired or necessary
performance characteristics. For example, useful panels or
laminates of such salt bonded woven substrates may comprise 10-50
layers per inch thickness. Such panels or laminates may be
installed in doors, sides, bottoms or tops of a vehicle to provide
armor and projectile protection. The panels may also be assembled
in the form of cases, cylinders, boxes or containers for protection
of many kinds of ordnance or other valuable and/or fragile material
such as ammunition, fuel and missiles as well as personnel.
Laminates may include layers of steel or other ballistic resistant
material such as carbon fiber composites, aramid composites or
metal alloys.
[0060] The aforesaid composites may be readily molded into articles
having contoured and cylindrical shapes, specific examples of which
include helmets, helmet panels or components, vests, vest panels as
well as vehicle protection panels, vehicle body components, rocket
or missile housings and rocket or missile containment units,
including NLOS (non-line of sight) systems. Such housings and
containment units would encase and protect a rocket or missile and
are used to store and/or fire missiles or rockets and could be
constructed using the composites described herein to protect their
contents from external objects such as bullets or bomb fragments.
Vest panels of various sizes and shapes may be formed for being
inserted into pockets located on or in the lining of existing or
traditional military vests. The combined use of such panels with
more traditional bulletproof vests may result in a lighter, more
flexible, and more readily adaptable vest that accommodates the
variety of sizes for different individuals. Similarly, one
embodiment is a helmet panel that has been contoured to fit inside
as a liner for a traditional helmet. In another embodiment, the
protective composite panel is secured on the outside of the helmet
with flexible and/or resilient helmet covers, netting, etc. In a
different embodiment, the helmet may include one or more contoured
or shaped composites as described herein to protect the wearer from
bullets or bomb fragments.
[0061] For penetration resistant vehicular armor, many different
sized and shaped protection panels may be formed of the composite
including floor, door, side and top panels as well as vehicle body
components contoured in the shape of fenders, gas tank, engine and
wheel protectors, hoods, and the like. As used herein, "vehicle"
includes a variety of machines, including automobiles, tanks,
trucks, helicopters, aircraft and the like. Thus, the penetration
resistant vehicle armor may be used to protect the occupants or
vital portions of any type of vehicle.
[0062] The aforesaid composite articles may also be combined with
other ballistic and penetration resistant panels of various shapes
and sizes. For example, the aforesaid composites may be paired with
one or more layers or panels of materials such as steel, aramid
resins, carbon fiber composites, boron carbide, or other such
penetration resistant materials known to those skilled in the art
including the use of two or more of the aforesaid materials,
depending on the armor requirements of the penetration resistant
articles required.
[0063] By way of example, a woven glass fiber substrate bonded with
strontium chloride was formed according to the previously described
procedure at a concentration of 0.5 grams salt per cc of open
substrate space. Layers of the substrate were coated with epoxy
resin and formed in a panel 12.5 in..times.12.5 in..times.0.5 in.
thick. The panel weighed 4.71 pounds, having material density of
0.06 pounds per cubic inch, comparing to 22% of the density of
carbon steel. Bullets fired from a military-issued Berretta gun
firing 9 mm 124-grain FMG bullets (9 g PMC stock number, full metal
jacket), at 20 yards did not fully penetrate the panel.
III. Overview of Example Anti-Ballistic Articles
[0064] FIG. 1A illustrates an example of a projectile-resistant
enclosure 10 having walls 20 comprising the anti-ballistic articles
described herein. As illustrated, the walls 20 can include three
panels: a first composite panel 25 and second composite panel 30
and a stress mitigation panel 28 disposed between the exterior
composite panel 25 and interior composite panel 30. Enclosure 10
can be used to protect equipment or personnel, for example as a
room on board a ship or aircraft, or can be a storage or transport
container. Due to the possibly large size of enclosure 10, the
lightweight paneled penetration resistant composites described
herein can be beneficial for providing ballistic protection while
complying with weight limitations that can be due to usage of
enclosure 10 on or within a vehicle.
[0065] FIG. 1B illustrates a cross-sectional view of one embodiment
of the walls of the enclosure of FIG. 1A. As illustrated, the walls
20 can include the three panels discussed above: a first composite
panel 25 and second composite panel 30 and a stress mitigation
panel 28 disposed between the composite panels 25, 30. In other
embodiments, walls 20 can include more composite panels and
intermediate stress mitigation panels. Composite panels 25, 30 can
include one or more layers of a woven penetration-resistant
composite such as those described above, and the layers of a panel
can have the same composition or different compositions as each
other and the layers of the other panel, depending on the
application.
[0066] The stress mitigation panel 28 can comprise a lightweight
material such that a weight of the mixed stack of composite panels
25, 30 and the stress mitigation panel 28 is less than the weight
of a stack including only composite panels. In some
implementations, the stress mitigating panel 28 includes a
compressible material and/or ductile material. For example, one
suitable material can be foam, for example open-cell
foam/reticulated foam, and the like.
[0067] In other implementations, the stress mitigating panel 28 can
be a frame, a spacing grid or matrix, or a lightweight 3D knitted
spacing fabric configured to create a gap between proximate
composite panels. For example, a frame can extend at least around
the edges of the composite panels to maintain a desired spacing gap
between proximate composite panels. The gap between composite
panels can be filled with gas (for example air) or liquid in some
embodiments.
[0068] In other implementations, the stress mitigating panel 28 can
comprise a hard, brittle material that cracks or shatters at
projectile impact speeds in order to redirect and/or absorb
force/stress propagating in the direction of projectile travel, or
to mitigate deformation of the impacted composite panel.
[0069] As illustrated, each composite panel 28, 30 can have a
thickness b and the stress mitigating panel 28 can have a thickness
a, with a total thickness c representing all three panels 25, 28,
30 stacked together. In some implementations, composite panels 28,
30 can have different thicknesses than one another. Some examples
of composite panels 28, 30 can have thicknesses between 0.2'' and
1.0''. In one example, a desired ratio of the stress mitigating
panel 28 to total thickness of the two composite panels 25, 30 with
the stress mitigating panel 28, a:c, can be between 1:10 and 1:2.
In another example, a thickness of the stress mitigating panel 28
is 10% to 50% of the overall thickness c of the multi-panel
ballistic composite article. Of course it should be realized that
embodiments are not limited to having only a single stress
mitigation panel disposed between two protective panels. For
example, the penetration resistant article may include 3, 4, 5, 6,
7 or more protective panels with a stress mitigation panel disposed
between each protective panel.
[0070] In other embodiments, the composite panels 25, 30 of
enclosure 10 may have regions of varying density, as described in
more detail with respect to FIG. 4, below. In such embodiments, the
stress mitigating panel 28 may be of a reduced thickness or may
even be omitted due to the stress mitigation capabilities of the
layer density variation. Alternatively, the stress mitigating panel
28 may be of the described width together with having layer density
variation within the composite panels 25, 30.
[0071] Accordingly, the enclosure 10 may be able to stop, or at
least reduce the impact velocity of, incoming projectiles more
effectively than enclosures with the same thickness, but having no
stress mitigation panels. For example, in some implementations the
walls 20 can be configured with sufficient composite panels and
intermediate stress mitigating panels to reduce the speed of an
impacting projectile traveling at an impact velocity of
approximately 8,300 ft/s by approximately half. The enclosure 10
having walls 20 including the anti-ballistic article having both
penetration resistant composite panels and stress mitigating panels
disposed between composite panels may accomplish such velocity
reductions at a fraction of the weight of multi-paneled penetration
resistant articles having composite panels alone, and using less
composite panels.
[0072] FIG. 2A illustrates a schematic diagram of a cross-section
of one embodiment of a projectile 230 impacting a penetration
resistant composite article 200A stacked with a compressible stress
mitigating panel 210. As shown, the compressible stress mitigating
panel 210 is disposed between first and second
penetration-resistant composite panels 205, 215. Each composite
panel 205, 215 is comprised of multiple composite layers 206, 216,
respectively. Although panel 205 is illustrated as having three
layers 206 and panel 215 is illustrated as having three layers 216,
the panels can have greater or fewer layers and can have different
numbers of layers from one another. In some embodiments, the layers
of a panel 205, 215 may have different densities from one another.
Penetration-resistant composite panels 205, 215 can comprise the
composites described above, for example having a plurality of
layers of woven fabric of polarized ballistic fibers, wherein a
metal salt, oxide, hydroxide or hydride are polar bonded onto the
polarized ballistic fibers.
[0073] Although only one compressible stress mitigating panel 210
is shown, some embodiments may use multiple compressible stress
mitigating panels to mitigate stress propagation between first
composite panel 205 and second composite panel 215.
[0074] The compressible stress mitigating panel 210 has an
uncompressed width of a.sub.1 corresponding to the gap between
composite panels 205, 215. However, as projectile 230 impacts the
first composite panel 205 (here, first refers to the impact-facing
side of the penetration resistant composite 200A) and deforms a
portion 220 of the first composite panel 205 around the impact site
235, the compressible stress mitigating panel 210 has a compressed
width of a.sub.2 resulting from the deformation of first composite
panel 205 in the direction of projectile travel. The compressed
width of a.sub.2 is sufficient to isolate the deformation of first
composite panel 205 so that the second composite panel 215 is not
weakened by the deformation 220 of the first composite panel 205
and thus retains its penetration-resisting potential.
[0075] As will be understood, if the first composite panel 205 and
second composite panel 215 were directly adjacent one another,
without the stress mitigating panel 210, the deformation 220 of the
first composite panel 205 would press against and deform the second
composite panel 215, thereby weakening the second composite panel
215 (for example weakening the composite crystal interlocking)
before the projectile 230 impacted the second composite panel 215.
Therefore, the stress mitigating panel 210 functions to isolate (or
substantially isolate) deformation of the first panel 205 to avoid
(or substantially avoid) pre-stressing the second panel 215 prior
to projectile impact.
[0076] FIG. 2B illustrates a schematic diagram of a cross-section
of one embodiment of a projectile 260 impacting a penetration
resistant composite 200B stacked with a force dispersing stress
mitigating panel 240. As shown, the force dispersing stress
mitigating panel 240 is disposed between first and second
penetration-resistant composite panels 265, 268, with each of the
composite panels 265, 268 comprising a number of layers 266, 269.
Although panel 265 is illustrated as having three layers 266 and
panel 268 is illustrated as having three layers 269, the panels can
have greater or fewer layers and can have different numbers of
layers from one another. In some embodiments, the layers of a panel
265, 268 may have different densities from one another. Force
dispersing stress mitigating panel 240 comprises, in some
embodiments, a brittle material configured to shatter, rather than
deform, under impact in order to substantially mitigate stress
propagation into composite panel 268. For example, force dispersing
stress mitigating panel 240 can redirect and/or absorb the kinetic
force of the projectile in its direction of travel or to mitigate
deformation of the composite panel 268. In some examples, force
dispersing stress mitigating panel 240 can be a ceramic such as
boron carbide or silicon carbide.
[0077] As projectile 260 impacts the first composite panel 265 at
the impact site 270, the force dispersing stress mitigating panel
240 can resist deformation of the first panel 265, instead
dispersing the force from impact laterally (that is,
perpendicularly to the direction of projectile travel) thereby
spreading the force across an area 250. As a result, cracks 245 may
form in force dispersing stress mitigating panel 240. In this
manner, the force dispersing stress mitigating panel 240 can
mitigate the stress propagation from the first composite panel 265
to the second composite panel 268.
[0078] In other embodiments, instead of comprising a material
configured to shatter upon impact, the stress mitigating panel can
comprise a non-compressible liquid that mitigates the stress
propagation from the first composite panel into the second
composite panel by distributing the force caused by deformation of
the first panel across some or all of the surface area of the
liquid. In some embodiments, the penetration resistant composite
articles 200A, 200B can be sealed to be waterproof. For example,
the penetration resistant composite articles 200A, 200B can be
sealed within a waterproof material in the shape of a foil, wrap,
coating or encasing, or a waterproof material comprising an epoxy,
plastic or metal.
[0079] FIGS. 3A-3C illustrate various embodiments of example panel
configurations 300A, 300B, 300C for a multi-panel penetration
resistant article. In FIGS. 3A-3C, the penetration resistant
composite panels 310, 410, 510 can be any of the compositions
described above, for example having a plurality of layers 311, 411,
511 of woven fabric of polarized ballistic fibers, wherein a metal
salt, oxide, hydroxide or hydride are polar bonded onto the
polarized ballistic fibers. The layers 311, 411, 511 within a panel
310, 410, 510 can have varying densities in some embodiments.
[0080] The stress mitigating panels of FIGS. 3A-3C can be any type
of stress mitigating panels as described above, for example a
compressible panel, brittle panel, an air gap, a frame, matrix, or
other structure for forming a gap, or a liquid panel. In some
embodiments, a stress mitigating panel 305, 405, 505 can be a
combination of the stress mitigating panels described above. For
example, stress mitigating panel 305, 405, 505 can include both a
force dispersing panel positioned to absorb the impact stress of an
incoming projectile after impacting a first composite panel and a
compressible panel disposed between the force dispersing projectile
and the next composite panel to cushion the next composite panel
from any stress cracking of the force dispersing panel. Another
example of stress mitigating panel can include both the force
dispersing panel and the compressible panel, with the compressible
panel positioned adjacent to the first-impacted composite panel and
the force dispersing panel positioned between the compressible
panel and the next composite panel to prevent excess deformation of
the first composite panel from pre-stressing the next composite
panel.
[0081] In some embodiments, the penetration resistant composites
300A, 300B, 300C can be sealed to be waterproof. For example, the
penetration resistant composites 300A, 300B, 300C can be sealed
within a waterproof material in the shape of a foil, wrap, coating
or encasing, or a waterproof material comprising an epoxy, plastic
or metal.
[0082] FIG. 3A illustrates an example panel configuration for a
mixed panel penetration resistant composite article 300A having
three penetration resistant composite panels 310 comprised of
composite layers 311 having stress mitigating panels 305 disposed
between the composite panels 310. Other embodiments can have
greater or fewer penetration resistant composite panels 310 with
corresponding intermediate stress mitigating panels 305 as needed
to achieve the desired projectile impact velocity reduction
characteristics of the penetration resistant composite article
300A. As shown, the penetration resistant composite article 300A
has an impact-facing side 320 that would be first impacted by the
projectile 315 and an opposing side 325 that would be proximate to
the person or equipment that the penetration resistant composite
article 300A was positioned to protect. Because of the intermediate
stress mitigating panels 305, the mixed panel penetration resistant
composite article 300A can provide for greater reduction of the
impact velocity of a projectile 315 than an article including a
corresponding number of directly adjacent composite panels. Where
lightweight materials are selected for stress mitigating panels
305, the mixed panel penetration resistant composite article 300A
can weigh less than a composite-only article having directly
adjacent composite panels that provide similar penetration
resisting capabilities.
[0083] FIG. 3B illustrates a penetration resistant composite
article 300B that is a variation of the panel configuration of FIG.
3A, having three penetration resistant composite panels 410
comprised of composite layers 411 with stress mitigating panels 405
disposed between the composite panels 410 and a hardened panel 430
at the opposing side 425 of the penetration resistant composite
article 300B. The illustrated configuration is provided for
purposes of example, and other embodiments than the one depicted
may have greater or fewer penetration resistant composite panels
410 with corresponding intermediate stress mitigating panels 405 as
needed to achieve the desired projectile impact velocity reduction.
Hardened panel 430 can comprise a ceramic, metal, or other suitably
hard material to stop the projectile 415 after passage through the
composite panels 410 and stress mitigating panels 405 has
sufficiently slowed the projectile 415.
[0084] The penetration resistant composite article 300B having the
hardened panel 430 at the opposing side 425 can be suitable, in
some examples, for wearable armor or other anti-ballistic purposes
where stopping, rather than merely slowing, the projectile is
desired. Though not depicted, in some wearable embodiments the
penetration resistant composite article 300B may further include a
force-absorbing panel between hardened panel 430 and the body of a
user in order to cushion the user from the force of the projectile
415 impacting the hardened panel 430.
[0085] Although shown as separate structures, in some embodiments
the hardened panel 430 can be integrated into the adjacent
composite panel 410, for example as a hardened woven layer or
layers of the layers 411 at the opposing side 425 of the panel
410.
[0086] FIG. 3C illustrates a penetration resistant composite
article 300C that is a variation of the panel configuration of FIG.
3A, having three penetration resistant composite panels 510
comprising layers 511 with stress mitigating panels 505 disposed
between the composite panels 510 and a hardened panel 535 at the
impact-facing side 520 of the penetration resistant composite
article 300C. The illustrated configuration is provided for
purposes of example, and other embodiments than the one depicted
may have greater or fewer penetration resistant composite panels
510 with corresponding intermediate stress mitigating panels 505 as
needed to achieve the desired projectile impact velocity reduction.
Hardened panel 530 can comprise a ceramic, metal, or other suitably
hard material to break off drill bits of some armor-piercing
projectiles. Accordingly, the penetration resistant composite
article 300C having the hardened panel 535 at the impact-facing
side 520 can be suitable, in some examples, for resisting
armor-piercing projectiles that may, if their drill bits are not
broken off prior to entering the composite panels 510, tear through
the composite panels 510.
[0087] Although shown as separate structures, in some embodiments
the hardened panel 535 can be integrated into the adjacent
composite layer 510, for example as a hardened woven layer or
layers of the layers 511 at the opposing side 520 of the panel
510.
[0088] FIG. 4 illustrates an embodiment of a multi-paneled
composite article 600 having composite panels 610, 620 with layers
of varying density and a stress mitigation panel 605. Stress
mitigation panel 605 can be any of the stress mitigation panels
described above, for example a compressible material, brittle
material, or gap.
[0089] As illustrated, first outer panel 610 includes three density
regions: a first region 611 having a high density, a second region
612 having a medium density, and a third region 613 having a low
density. For example, first region 611 may be made with a salt
loading density of 0.6 g/cm, second region 612 may be made with a
salt loading density of 0.4 gm/cm and third region 613 may act as a
stress mitigation region and be made with a salt loading density of
0.2 gm/cm. Each region 611, 612, 613 can include one or more
composite layers or woven fabric. Similarly, second inner panel 620
includes three loading density regions: a first region 621 having a
high density, a second region 622 having a medium density, and a
third region 623 having a low density. For purposes of simplicity,
each region 611, 612, 613, 621, 622, 623 is illustrated as a single
layer, however each region can include one or more composite
layers. The composite layers of panels 610, 620 can be made of any
of the substrates and bonded materials described above. Although
three density regions are shown, other embodiments of panels 610,
620 may have two, or four or more, different density regions.
Density regions can be arranged, as illustrated, from greatest
density to lowest density, or can be arranged in repeating pattern
of two or more different density regions.
[0090] In some embodiments, the high density region 611 can be
positioned at the impact-facing side of the article 600. When a
ballistic projectile contacts the high density region 611 of panel
610, it may deform that region or first layers within the region
611. That deformation may result in a shock wave, or pieces of the
impacted layers, impacting the layer(s) in adjacent region(s) 612,
613 in the panel 610. The relatively lower density of these regions
612, 613 may allow the shock wave or debris to dissipate prior to
reaching the second panel 620.
[0091] Although the article 600 is illustrated with stress
mitigation panel 605, in some embodiments the article 600 can omit
the stress mitigation panel 605 entirely. Thus, in this embodiment,
each panel having differing densities is placed adjacent one
another and the area of reduced density within each panel acts as a
stress mitigation layer due to its reduced density. In other
embodiments, stress mitigation panel 605 can be included but can
have a relatively smaller thickness compared to articles with
homogenously dense composite panels.
[0092] In one embodiment, the ballistic article is made up of a
plurality of panels, wherein each panel has a first area of high
density, and a second stress mitigation region of reduced density.
In this embodiment, the panels are placed directly adjacent one
another and the second areas of reduced density within each panel
act as stress mitigation region to reduce the pre-stress force of
the projectile as it traverses each panel.
[0093] In another embodiment, the entire article 600 is made from a
single panel that includes regions of fabric providing varying
composite densities within the panel, as discussed above.
IV. Other Embodiments
[0094] Although discussed herein primarily in the context of an
enclosure, it will be appreciated that the mixed, multi-paneled
penetration resistant composite articles described above can be
implemented in a variety of other circumstances. The penetration
resistant composite articles can also be implemented as wearable
body armor or vehicle armor, for example as a protective layer over
the bottom of a helicopter.
V. Terminology
[0095] Features, materials, characteristics, or groups described in
conjunction with a particular aspect, embodiment, or example are to
be understood to be applicable to any other aspect, embodiment or
example described herein unless incompatible therewith. All of the
features disclosed in this specification (including any
accompanying claims, abstract and drawings), and/or all of the
steps of any method or process so disclosed, may be combined in any
combination, except combinations where at least some of such
features and/or steps are mutually exclusive. The protection is not
restricted to the details of any foregoing embodiments. The
protection extends to any novel one, or any novel combination, of
the features disclosed in this specification (including any
accompanying claims, abstract and drawings), or to any novel one,
or any novel combination, of the steps of any method or process so
disclosed.
[0096] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of protection. Indeed, the novel
methods and systems described herein may be embodied in a variety
of other forms. Furthermore, various omissions, substitutions and
changes in the form of the methods and systems described herein may
be made. Those skilled in the art will appreciate that in some
embodiments, the actual steps taken in the processes illustrated
and/or disclosed may differ from those shown in the figures.
Depending on the embodiment, certain of the steps described above
may be removed, others may be added. Furthermore, the features and
attributes of the specific embodiments disclosed above may be
combined in different ways to form additional embodiments, all of
which fall within the scope of the present disclosure.
[0097] Although the present disclosure includes certain
embodiments, examples and applications, it will be understood by
those skilled in the art that the present disclosure extends beyond
the specifically disclosed embodiments to other alternative
embodiments and/or uses and obvious modifications and equivalents
thereof, including embodiments which do not provide all of the
features and advantages set forth herein. Accordingly, the scope of
the present disclosure is not intended to be limited by the
specific disclosures of preferred embodiments herein, and may be
defined by claims as presented herein or as presented in the
future.
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