U.S. patent application number 14/208017 was filed with the patent office on 2015-03-26 for light-weight semi-rigid composite anti-ballistic systems with engineered compliance and rate-sensitive impact response.
This patent application is currently assigned to Cubic Tech Corporation. The applicant listed for this patent is Cubic Tech Corporation. Invention is credited to Roland Joseph Downs, Heiner W. Meldner.
Application Number | 20150082976 14/208017 |
Document ID | / |
Family ID | 51168332 |
Filed Date | 2015-03-26 |
United States Patent
Application |
20150082976 |
Kind Code |
A1 |
Meldner; Heiner W. ; et
al. |
March 26, 2015 |
LIGHT-WEIGHT SEMI-RIGID COMPOSITE ANTI-BALLISTIC SYSTEMS WITH
ENGINEERED COMPLIANCE AND RATE-SENSITIVE IMPACT RESPONSE
Abstract
Composite anti-ballistic systems having multiple nested
sub-laminates manufactured from layers of unidirectional
monofilaments made from engineering fibers with anti-ballistic
properties embedded in polymer matrix materials and interfacial
materials engineered for controlled compliance, deformation, energy
release and rate sensitive behavior.
Inventors: |
Meldner; Heiner W.; (Reno,
NV) ; Downs; Roland Joseph; (Mesa, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cubic Tech Corporation |
Mesa |
AZ |
US |
|
|
Assignee: |
Cubic Tech Corporation
Mesa
AZ
|
Family ID: |
51168332 |
Appl. No.: |
14/208017 |
Filed: |
March 13, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61780803 |
Mar 13, 2013 |
|
|
|
Current U.S.
Class: |
89/36.02 ;
428/110; 428/114; 428/216; 428/319.3; 428/413; 428/423.1;
428/480 |
Current CPC
Class: |
Y10T 428/31551 20150401;
F41H 1/02 20130101; Y10T 428/24099 20150115; Y10T 428/31786
20150401; Y10T 428/24132 20150115; Y10T 428/249991 20150401; F41H
5/0485 20130101; F41H 5/04 20130101; Y10T 428/24975 20150115; Y10T
428/31511 20150401 |
Class at
Publication: |
89/36.02 ;
428/114; 428/110; 428/413; 428/423.1; 428/480; 428/319.3;
428/216 |
International
Class: |
F41H 1/02 20060101
F41H001/02; F41H 5/04 20060101 F41H005/04 |
Claims
1. An antiballistic composite comprising: (a) multiple sub-laminate
layers; and (b) viscoelastic dilatory material distributed as
interlayers between said sub-laminate layers; wherein said
viscoelastic dilatory material converts from soft compliant
material to stiff interlayers when said composite is subjected to
impact.
2. The composite of claim 1, wherein said viscoelastic dilatory
material comprises a rate-sensitive high-rate stiffening polymer or
a polymer foam.
3. The composite of claim 1, wherein said viscoelastic dilatory
material bonds each of said multiple sub-laminate layers together
into a single panel.
4. The composite of claim 1, wherein said interlayers are about
1-10 microns in thickness.
5. The composite of claim 1 comprising at least ten sub-laminate
layers.
6. The composite of claim 1, wherein each sub-laminate layer
comprises at least one unidirectional tape comprising parallel
monofilaments embedded in a resin.
7. The composite of claim 6, wherein said monofilaments have
diameters less than about 20 microns and wherein spacing between
individual monofilaments within an adjoining strengthening group of
monofilaments is within a gap distance in the range between
non-abutting monofilaments up to about nine times the monofilament
major diameter.
8. The composite of claim 6, wherein said monofilaments have
modulus greater than 1.0.times.10.sup.6 psi and failure strength
greater than greater than 1.0.times.10.sup.5 psi.
9. The composite of claim 6 comprising two unidirectional tapes
oriented as a cross-ply, wherein the parallel monofilaments present
in one tape are 90.degree. relative to the parallel monofilaments
present in the other tape.
10. The composite of claim 6, wherein said tapes total four in a
ply group, and wherein the parallel monofilaments within each of
said four tapes have relative orientation of
0.degree./45.degree./90.degree./-45.degree..
11. The composite of claim 6, wherein said tapes total nine in a
ply group, and wherein the parallel monofilaments within each of
said nine tapes have a relative orientation of
0.degree./22.5.degree./45.degree./67.degree./90.degree./-67.degree./-45.d-
egree./-22.5.degree./0.degree..
12. The composite of claim 6, wherein said monofilaments are
extruded or pultruded.
13. The composite of claim 6, wherein said resin comprises from 1%
to 30% of the total areal weight of said tape.
14. An antiballistic device comprising at least one antiballistic
composite, said antiballistic composite comprising: (a) multiple
sub-laminate layers; and (b) viscoelastic dilatory material
distributed as interlayers between said sub-laminate layers;
wherein said viscoelastic dilatory material converts from soft
compliant material to stiff interlayers when said composite is
subjected to impact.
15. The device of claim 14, wherein each sub-laminate layer
comprises at least one unidirectional tape comprising parallel
monofilaments embedded in a resin.
16. The device of claim 14 comprising multiple antiballistic
composites nested into a plate system.
17. The device of claim 14 further comprising a ceramic or metallic
component.
18. The device of claim 14, wherein said viscoelastic dilatory
material comprises a rate-sensitive high-rate stiffening polymer or
a polymer foam.
19. The device of claim 14, wherein said device is worn to provide
anti-penetration, load spreading, impact management and shock
management to the wearer.
20. The device of claim 19, wherein said device is a vest.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 61/780,803, filed Mar. 13, 2013, which is
incorporated herein in its entirety.
BACKGROUND
[0002] Related disclosures are found in U.S. Pat. No. 5,470,062,
entitled "COMPOSITE MATERIAL FOR FABRICATION OF SAILS AND OTHER
ARTICLES," which was issued on Nov. 28, 1995; and U.S. Pat. No.
5,333,568, entitled "MATERIAL FOR THE FABRICATION OF SAILS" which
was issued on Aug. 2, 1994; and U.S. patent application Ser. No.
13/168,912, filed Jun. 24, 2011 entitled "WATERPROOF BREATHABLE
COMPOSITE MATERIALS FOR FABRICATION OF FLEXIBLE MEMBRANES AND OTHER
ARTICLES,"; and U.S. patent application Ser. No. 13/197,741, filed
Aug. 3, 2011 entitled "SYSTEM AND METHOD FOR THE TRANSFER OF COLOR
AND OTHER PHYSICAL PROPERTIES TO LAMINATE COMPOSITE MATERIALS AND
OTHER ARTICLES", the contents of all of which are hereby
incorporated by reference for any purpose in their entirety.
[0003] This invention relates to providing improved
monofilament-related products, methods, and equipment. More
particularly, this invention relates to providing systems for
design and manufacture of products using the technologies and
useful arts herein taught and embodied. Even more particularly,
this invention provides improvements in efficiently controlling
properties of fabric-related products, including but not limited
to: weight, rigidity, penetrability, waterproof-ability,
breathability, color, mold-ability, cost, customizability,
flexibility, package-ability, etc., including desired combinations
of such properties.
[0004] In the past, there has been difficulty in achieving desired
combinations of such properties, especially with regard to
fabric-related products like clothing and shoes, camping and hiking
goods, comfortable armor, protective inflatables, etc.
[0005] This invention more particularly relates to providing a
system for improved composite anti-ballistic systems. More
particularly this invention relates to providing a system for
composite anti-ballistic systems utilizing composite materials of
varying properties.
[0006] Current soldier personal protection for anti-ballistic
protection is generally either by the common SAPI armor plates or
by conventional soft vests. Rigid ceramic SAPI plates provide
effective protection, but they limit mobility and are
uncomfortable, which distracts soldiers in the field and induces
unnecessary rapid fatigue. Additionally, SAPI plates are very
susceptible to serious damage due to impacts endemic to soldier's
operations in the field; and the damage is difficult to detect,
impossible to repair and can result in serious or total degradation
in ballistic protection. SAPI plates also have poor protection of
closely-spaced multiple hits.
OBJECTS AND FEATURES OF THE INVENTION
[0007] A primary object and feature of the present invention is to
provide a system overcoming the above-mentioned problem.
[0008] Another primary object and feature of the present invention
is to provide a system to fine-tune, at desired places on a
product, directional control of rigidity/flexibility/elasticity
properties.
[0009] Yet another primary object and feature of the present
invention is to provide products combining extreme light weight
with extreme strength.
[0010] It is a further object and feature of the present invention
to provide such a system providing continuous bulk manufacture of
such products and their constituent parts.
[0011] Another object and feature of the present invention is to
provide adaptability to the various stations of such continuous
bulk manufacturing system.
[0012] It is a further object and feature of the present invention
to provide such a system providing composite anti-ballistic
devices.
[0013] Another object and feature of the present invention is to
provide such a system having multiple nested sub-laminates
manufactured from layers of unidirectional monofilaments.
[0014] A further object and feature of the present invention is to
provide such a system made from engineering fibers with
anti-ballistic properties.
[0015] It is another object and feature of the present invention to
provide such a system comprising polymer matrix materials and
interfacial materials engineered for controlled compliance,
deformation, energy release and rate sensitive behavior.
[0016] A further primary object and feature of the present
invention is to provide such a system that is efficient,
inexpensive, and handy. Other objects and features of this
invention will become apparent with reference to the following
descriptions.
SUMMARY OF THE INVENTION
[0017] In accordance with a preferred embodiment hereof, this
invention provides a laminate including reinforcing elements
therein, such reinforcing elements including at least one
unidirectional tape having monofilaments therein, all of such
monofilaments lying in a predetermined direction within the tape,
wherein such monofilaments have diameters less than 20 microns and
wherein spacing between individual monofilaments within an
adjoining strengthening group of monofilaments is within a gap
distance in the range between non-abutting monofilaments up to nine
times the monofilament major diameter.
[0018] Moreover, it provides such a laminate wherein such
monofilaments are extruded. Additionally, it provides such a
laminate wherein such reinforcing elements include at least two
unidirectional tapes, each having extruded monofilaments therein,
all of such monofilaments lying in a predetermined direction within
the tape, wherein such monofilaments have diameters less than 20
microns and wherein spacing between individual monofilaments within
an adjoining strengthening group of monofilaments is within a gap
distance in the range between non-abutting monofilaments up to nine
times the monofilament major diameter. Also, it provides such a
laminate wherein each of such at least two unidirectional tapes
includes larger areas without monofilaments therein and wherein
such larger areas comprise laminar overlays comprising smaller
areas without monofilaments.
[0019] In addition, it provides such a laminate wherein such
smaller areas comprise user-planned arrangements. And, it provides
such a laminate further comprising a set of water-breathable
elements comprising laminar overlays of such smaller areas.
Further, it provides such a laminate further comprising a set of
other laminar overlays. Moreover, it provides such a laminate
wherein a first one of such at least two unidirectional tapes
includes monofilaments lying in a different predetermined direction
than a second one of such at least two unidirectional tapes.
[0020] Additionally, it provides such a laminate wherein a
combination of the different predetermined directions of such at
least two unidirectional tapes is user-selected to achieve laminate
properties having planned directional rigidity/flexibility. Also,
it provides such a laminate comprising a three-dimensionally
shaped, flexible composite part. In addition, it provides such a
product comprising multiple laminate segments attached along
peripheral joints. And, it provides such a product comprising at
least one laminate segment attached along peripheral joints with at
least one non-laminate segment. Further, it provides such a product
comprising multiple laminate segments attached along area
joints.
[0021] Even further, it provides such a product comprising at least
one laminate segment attached along area joints with at least one
non-laminate segment. Moreover, it provides such a product
comprising at least one laminate segment attached along area joints
with at least one unitape segment. Additionally, it provides such a
product comprising at least one laminate segment attached along
area joints with at least one monofilament segment. Also, it
provides such a product further comprising at least one rigid
element.
[0022] In accordance with another preferred embodiment hereof, this
invention provides a product wherein such at least one
unidirectional tape is attached to such product. In accordance with
a preferred embodiment hereof, the present system provides each and
every novel feature, element, combination, step and/or method
disclosed or suggested by this patent application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 shows a diagramatic view illustrating at least one
composite laminate material according to a preferred embodiment of
the present invention.
[0024] FIG. 2 shows an enlarged detail view of detail A of FIG. 1
according to the preferred embodiment of FIG. 1.
[0025] FIG. 3 shows a data graph, illustrating percent performance
vs. number of layers, according to the preferred embodiment of FIG.
1.
[0026] FIG. 4 shows a diagramatic view, illustrating flexibility of
at least one panel of such at least one composite laminate
material, according to the preferred embodiment of FIG. 1.
[0027] FIG. 5 shows a diagramatic view, illustrating impact loading
of at least one panel of such at least one composite laminate
material, according to the preferred embodiment of FIG. 1.
[0028] FIG. 6 shows a diagramatic view, illustrating a comparative
thickness of at least one panel of such at least one composite
laminate material, according to the preferred embodiment of FIG.
1.
[0029] FIG. 7 shows a diagramatic view, illustrating intralaminar
hybridization, according to the preferred embodiment of FIG. 1.
[0030] FIG. 8 shows a diagramatic view, illustrating comingled
filaments, according to the preferred embodiment of FIG. 1.
[0031] FIG. 9 shows use of sublaminates & interlayers to reduce
peak impact loads.
TABLE-US-00001 [0032] BRIEF GLOSSARY OF TERMS AND DEFINITIONS
Adhesive: A curable resin used to combine composite materials.
Anisotropic: Not isotropic; having mechanical and or physical
properties which vary with direction at a point in the material.
aerial weight: The weight of fiber per unit area, this is often
expressed as grams per square meter (g/m.sup.2). Autoclave: A
closed vessel for producing an environment of fluid pressure, with
or without heat, to an enclosed object which is undergoing a
chemical reaction or other operation. B-stage: Generally defined
herein as an intermediate stage in the reaction of some
thermosetting resins. Materials are sometimes pre cure to this
stage, called "prepregs", to facilitate handling and processing
prior to final cure. C-stage: Final stage in the reaction of
certain resins in which the material is relatively insoluble and
infusible. Cure: To change the properties of a polymer resin
irreversibly by chemical reaction. Cure may be accomplished by
addition of curing (cross-linking) agents, with or without
catalyst, and with or without heat. Decitex (DTEX): Unit of the
linear density of a continuous filament or yarn, equal to 1/10th of
a tex or 9/10th of a denier Dyneema .TM.
Ultra-high-molecular-weight polyethylene fiber by DSM Filament: The
smallest unit of a fiber-containing material. Filaments usually are
of long length and small diameter. Polymer: An organic material
composed of molecules of monomers linked together. Prepreg: A
ready-to-cure sheet or tape material. The resin is partially cured
to a B-stage and supplied to a layup step prior to full cure. Tow:
An untwisted bundle of continuous filaments. UHMWPE:
Ultra-high-molecular-weight polyethylene. A type of polyolefin made
up of extremely long chains of polyethylene. Trade names include
Spectra .RTM. and Dyneema .RTM. Unitape Uni-Directional tape (UD
tape) - flexible reinforced tapes (also referred to as sheets)
having uniformly- dense arrangements of reinforcing fibers in
parallel alignment and impregnated with an adhesive resin. UD tapes
are typically B-staged and form the basic unit of most CT composite
fabrics.
DETAILED DESCRIPTION OF THE BEST MODES AND PREFERRED EMBODIMENTS OF
THE INVENTION
[0033] Referring to FIGS. 1-9, light-weight semi-rigid composite
anti-ballistic systems 100 described herein is a pure composite
anti-ballistic system based on multiple nested sub-laminates
manufactured from layers of unidirectional monofilaments made from
engineering fibers with anti-ballistic properties embedded in
polymer matrix materials and interfacial materials engineered for
controlled compliance, deformation, energy release and rate
sensitive behavior. These layers are oriented in multiple
directions to distribute the impact loads, control deformation and
dissipate impact energy to provide ballistic protection in a form
that has sufficient, controlled rigidity under ballistic impact to
provide the necessary functions of anti penetration, load
spreading, impact energy management and shock management. Such
orientation of layers further provide sufficient flexibility and
compliance when worn that loss of mobility and range of motion is
minimized, and wearer comfort is improved. These improvements
enhance combat effectiveness and minimize operator fatigue due to
reduced mobility and restriction of range of motion encountered
with rigid SAPI plates.
[0034] Although the system may be integrated into a system also
utilizing a ceramic or metallic component, the pure composite
implementation of the system is not susceptible to impact damage
like observed in a ceramic SAPI plate and is insensitive to most
normal in-service incidental impacts. The system also exhibits
superior protection against multiple close spaced hits. Since the
system does not absorb significant percentages moisture, the
resulting anti-ballistic system does not gain weight or become
water-logged due to hydrolysis. The system also is protected from
degradation due to flex fatigue, UV radiation and exposure to most
agents or chemicals normally encountered.
[0035] The system preferably comprises at least one composite
anti-ballistic device. Such at least one composite anti-ballistic
device preferably comprises improved compliance stretchability and
flexibility for higher mobility and less
range-of-motion-restriction by preferably using at least one
multi-layer, multi-directional sublayer approach.
[0036] Such at least one flexible ballistic panel is preferably
made from layers of sub-laminates. The sub-laminates of the panel
system are preferably manufactured from layers of unidirectional
monofilaments of engineering fibers having antiballistic
properties, a modulus greater than 1.0.times.106 psi and a failure
strength in excess of 100,000 psi.
[0037] Such at least one multi-layer, multi-directional
sub-laminate approach preferably uses thin (less than 6
monofilament diameters for conventional monofilaments, less than
0.005'' for ultra thin or nano monofilaments, ropes, yarns fibers)
unitape tape layers, alternately preferably intra or interlaminar
hybridization of filaments. Such filaments preferably comprise
various engineering fibers with a Young's Modulus of over 1 msi and
an ultimate tensile strength of more than 100 KSI). Such
Engineering fibers preferably include: UBMWPE (available under the
trade names Dyneema and Spectra), Aramid (available under the trade
names Kevlar and Twaron), PBO fiber under the Zylon name, liquid
crystal polymer Vectran, glass fibers such as E and S glass, M5
fibers, carbon and para-aramid under the Technora name. Such
Engineered fibers preferably further include nano-filaments,
nano-ropes, nano-yarns, nano-tows, nano-powder, and/or nano-film
that preferably may be incorporated into the unitape layer, with
the unitape and/or applied to the outer surface of the unitape.
Such at least one nano-material may be applied to the outer surface
of individual monofilaments by nano spray, electron beam
deposition, sputtering, vapor deposition, atmospheric plasma
deposition, infusion, or as part of polymer coating. Such coating
shall preferably comprises a cross linking system with a thermal
activation, alternately preferably two part self curing,
alternately preferably radiation cured such as E-beam, RF cured, UV
cured, or heat cured. The surface of the fibers, the surface of the
nano-component and/or the polymer resin may all be provided with
chemically reactive functional groups that create a strong chemical
bond between the monofilament surface, the nano-component, the
short fiber component or the resin, to improve adhesion and enhance
energy dissipation.
[0038] Individual unitape plies may vary from 1.5-80 g/m 2 of areal
density. The unitape preferably contain one single class of fiber
such as Aramid, UHMWPE, glass, etc., alternately preferably contain
a combination of classes or styles (same class of fiber but
different spec for example), alternately preferably any combination
of the above preferably in a predetermined pattern or
configuration. The different fiber types may be discrete
alternating sets of each material across the width or thickness of
the unitape or they can be distributed in a uniform intermixed or
comingled configuration. These unitapes may be layered in any
combination of materials within each layer of the sub-laminate.
Examples are having a sub-laminate made from only one grade of
Aramid such as Kevlar or UHMWPE Dyneema monofilament in each
unitape in the sub-laminate, or by using one or more different
unitapes in the sub-laminate wherein each unitape is made from one
type of monofilament. Another example is having a unitape made up
of hybrid unitape with multiple fiber types incorporated in each
layer but having all the unitape in the sub-laminate made from the
same specification of hybrid. Yet another example is the most
general where the sub-laminate is made from unitapes with multiple
mixes of fiber in the unitape and multiple types of unitape used to
make up the sub-laminate.
[0039] Individual unitapes within the sub-laminate may alternately
preferably also be made from differing fiber areal densities.
Hybrid sub-laminates of this kind can provide improved ballistic
performance when one of the types of fiber may provide superior
protection under some conditions but may not provide adequate
protection under another set of conditions. A good example would be
the use of UHMWPE monofilaments, which provide excellent
anti-ballistic protection under most conditions but are limited in
their ability to protect from some impacts by incendiary
projectiles that exceed temperature limits of the base polymer.
Kevlar or PBO hybrids can improve the ability of the UHMWPE base
laminate to protect against the incendiary projectile due to the
higher temperature capabilities of the aramid or PBO monofilaments.
Using monofilaments of dissimilar properties can also improve the
ballistic impact performance because the interactions of the
dissimilar monofilaments can generate significant impact energy
absorption, shock dissipation and controlled deformations due to
the incompatibility of strains between the dissimilar
monofilaments.
[0040] The minimum number of plies of the sub-laminate can be
determined by semi-empirical methods to find the approximate number
of plies needed to bring the specific ballistic performance of the
sheet up to the level most comparable to the monolithic plate case
by obtaining the optimum "lamination effect." At a certain number
of unitape layers the improvement in ballistic performance levels
off and the number of plies is determined by the use of a
sub-laminate thickness that provides the degree of flex desired, as
shown in FIG. 1.
[0041] Each unidirectional ply can be oriented in any given
in-plane angle. The simplest is a two-direction, cross-ply
[0.degree./90.degree. ] configuration which is easy to fabricate
but often does not provide the best ballistic protection nor the
best resistance to global panel deformation nor to "back wall
deformation." Back wall deformation is the area directly under the
impact area where the laminate is extruded & pushed back into
the body of the wearer, which can cause injury or incapacitation.
Excessive deformation also degrades the ballistic protection for
multi-hit impacts closely spaced. For this reason it is desirable
to have a number of angles selected. Three provide some improvement
but four angles spaced at the
0.degree./45.degree./90.degree./-45.degree. orientations gives the
better performance. Some additional improvement can be obtained by
adding another set of ply angles such as at 22.5.degree. increments
(0.degree./22.5 .degree./45
.degree./67.degree./90.degree./-67.degree./-45.degree./-22.5.degree./0.de-
gree. for example), or at +/-30.degree. or +/-60.degree.. The
sub-laminates can be made of stacked repeating sets of these ply
groups to build up the desired number of unitape layers in order to
achieve the required ballistic performance and flexibility.
[0042] The resin content preferably ranges from 1% to 30% of the
total areal weight of the unitape with the lower resin contents
generally providing better ballistic performance. High and low
resin content unitape can be combined in various stacking sequences
and layup patterns.
[0043] Thin layers of polymer films, non-wovens, and layers of
nano-fibers or films preferably can be located at one or more
unitape interfaces to improve or modify ballistic performance.
[0044] Resin materials may preferably be epoxy base, cyanate ester
base, or polyester based resins of varying molecular weight or
composition combined with various curing agents to provide the
desired matrix properties. Matrix materials preferably may also be
thermoplastic polyurethane, alternately preferably block
copolyesters, alternately preferably two part polyurethane either
with the aromatic or aliphatic isocyanate curing mechanism,
alternately preferably ceramics, alternately preferably E-beam
deposition polymers, alternately preferably silicones, or others.
Resins may preferably be in hot melt, alternately preferably
aqueous solutions, alternately preferably solutions with organic or
inorganic solvent, alternately preferably water or solvent
dispersions, alternately preferably powders, alternately preferably
spunbonded films, alternately preferably extruded sheets,
alternately preferably cast sheets. The cast or extruded sheets
preferably may be homopolymer, alternately preferably a multilayer
coextrusion, alternately preferably co-cast onto a carrier, film,
paper, or cloth or the film may be unsupported.
[0045] Such at least one multilayer, multidirectional sub-laminates
preferably comprises unitape of pultruded monofilaments preferably
to provide the laminate with a multidirectional-layered
network.
[0046] The bending stiffness of a ballistic plate or sheet,
neglecting effects of transverse strain, preferably is proportional
to the section modulus of the plate or sheet, preferably according
to the formula:
Section Mod=Z=BD.sup.2/6
[0047] Where B is the width and D is the thickness of the plate or
sheet.
[0048] For comparison purposes only, we set the width normalized to
1 to determine the effects of the sheet or plate thickness on the
flexibility of comparable plates and sheets. One inch is a common
thickness for composite sheets because it roughly gives 5 lbs/ft2.
For the 1'' plate section, the modulus=Z=BD2/6=(1) (1)/6=1/6. Now
let examine the effect on flexibility by going thinner, starting at
0.020'' and going up in 0.020'' increments to 0.10''. Z=(1)
(1/50)2/6=1/(6) (2500), so the 0.020''=1/2500 of bending stiffness
of the 1'' since Z is proportional to the thickness of the panel
squared. If t=0.030 the Z=1/1111. If t=0.040 the Z=(1/25)2
[0049] For a 1'' stack of the 0.020'' sheet, total flex=to the sum
of section modulus: Zeff=.SIGMA.2i (Z.times.50) 1/2500*(50)=1/50;
and I=1 to 33.3; Zeff=.SIGMA.2i=1/33.3. As one can see from the
pattern, the flexibility of a panel made up of sub-laminate of
equalizing total thickness, if all sub-laminate thicknesses are the
same proportion using this relationship, then we can break the
total desired panel thickness into a number of sub-laminates that
provide the necessary increase in flexibility. If a thickness of
0.020'' is chosen for the sub-laminate sheet, then the effective
stiffness is 1/50 times lower since the bending stiffness of the
stack of 50 0.020'' sub-laminates is 50 time less than a monolithic
1'' ballistic plate.
[0050] If engineered properly, a panel made from the sub-laminate
may have performance ranging from minimal reduction in ballistic
performance to actually being higher in ballistic protection than
solid rigid plates, while still being flexible. The sub-laminate
may be used as discrete sheets with maximum flexibility or they may
be lightly bonded together with a thin layer of compliant
rate-sensitive dilation material embedded in compliant foam.
[0051] Bonding the sub-laminate together in such a way decreases
the flexibility of the panel but preferably still allows for a
compliant panel, especially if the panel does not need to undergo
large deformations as is the case with ballistic plates. It is
preferable for a ballistic plate to impart just enough "give" into
the panel to provide the necessary level of mobility and
comfort.
[0052] This is a subjective parameter that depends upon the total
thickness of the ballistic panel system, the properties of the
monofilament in the sub-laminate and the degree of compliance
engineered at the interfaces between the laminates.
[0053] Although the sub-laminate system has sub-engineered flexural
properties, much of the flexibility is due to the low shear &
young's modulus of the viscoelastic dilatory foam materials at the
interface bonding the sub-laminate panels into a single panel.
Dilatory materials are very rate-sensitive and undergo a transition
from highly compliant elastomeric material to highly rigid, solid
material. Under impact, the rate of sensitive dilatory layers
converts from a soft compliant material into a stiff interlayer
that locks up the sub-laminates together so that they act as a
solid panel, which means that impact stiffness of a panel increases
to close to that of a solid ballistic panel.
[0054] The rigidness of the panel under impact spreads the impact
loads and maintains the structural integrity of the panel during
the impact. Since this is a viscoelastic effect, the rate at which
the interlayers transform from soft to rigid can be controlled to
manage the impact and spread the force of the impact event over a
longer period of time. Spreading the impact load over a longer time
period reduces the magnitude of the impact loads, and the load rate
preferably can be adjusted to provide optimal load transfer to the
individual sub-laminates to provide the highest level of protection
from each individual ballistic sub-laminate, as shown in FIG.
1B.
[0055] Compliant, viscoelastic interlinear layer of rate-sensitive,
higher rate stiffening polymer and polymer foam, as shown in FIG.
1A.
[0056] Panel is flexible under normal use due to sub-laminates, as
shown in FIG. 4.
[0057] Under impact loads the rate-sensitive interlace rigidizes or
"freezes" the plate into the equivalent of one-piece panel with no
sub-laminate, as shown in FIG. 5.
[0058] At least one area of design flexibility on the sub-laminate
panels is the ability to select the thickness of the viscoelastic,
dilation interlayers. The most effective of the commercial systems
are in the form of lightweight foams that allow for the
incorporation of relative thick layers with minimal weight
increase. The flexibility of the panel is enhanced by the case of
thicker compliant layers, which is derivable from a mobility and
comfort perspective. Use of thicker compliant layers also increases
the thickness of the global panel system. This thickness increase
by itself does not generally limit mobility or restrict motion
since flexibility is actually enhanced. This increased thickness
does significantly increase the effective section modulus of the
global panel system during the transient rigid state under impact
which can significantly increase the "effective stiffness" of the
rigid panel, as shown in FIG. 6.
[0059] For example, the one 1'' monolithic panel is broken up into
4 sub-laminates with viscoelastic layers that bring the total
thickness of the panel up to 1.5'', in this case the section
modulus of the monolithic plate is preferably determined by the
formulas:
Section Modulus=(1).sup.2/6 for monolithic
Section Modulus=(1.5).sup.2/6 for sub-laminate
SM|.sub.mono=1/6
SM|.sub.sub=2.25/6
[0060] Note: so the effective stiffness of the rigid panel under
impact has 2.25 times the stiffness and resistance to
deformation.
[0061] The "rigidized" compliance layer can act as a core material
under impact to improve the structural properties of panel system
globally. The viscoelastic layers preferably can also be engineered
to provide some progression of load transfer into the individual
sub-laminates as the impact event progresses through the panel
system which can improve load spread, energy management and
contribute to enhanced anti-penetration.
[0062] Additionally, applicant's engineered viscoelastic dilation
layers preferably provide improved anti-ballistic properties, and
improved flexibility for better mobility and increased range of
motion without adding excessive weight and/or bulk. This
rigidizing, or "freezing," behavior under impact load preferably
provides multiple benefits including: 1. distributing the impact
loads, to spread them within the assembly reducing maximum peak
loads and associated injury; 2. restricting deformation of the
panel in the out-of-plane direction, thus reducing "back wall
deformation" that is a measure of how much the panel is deflected
inward towards the body of the wearer; 3. increasing the area of
the panel used to resist the impact for better energy absorption
and shock dissipation; and, 4. allowing improved resistance to
projectile penetration by optimizing the progressive response of
the panel system to the projectile as it strikes and enters the
panel.
[0063] The system preferably further comprises hybridization of
fiber types by combinations of interlaminar hybridization
(different ballistic fiber type layer by layer), alternately
preferably intralaminar hybridization (one or more different fiber
types within a layer to a predetermined pattern or design), as
shown in FIG. 7, alternately preferably comingled (two or more
fiber types generally uniformly mixed at the monofilament level),
as shown in FIG. 8.
[0064] The system alternately preferably comprises hybridization
via different fiber types (i.e. Dyneema and Kevlar). Alternately
preferably, the system comprises hybridization via different
styles, alternately preferably different product forms, alternately
preferably different mechanical properties of the same or similar
fiber or monofilament (i.e. Dyneema SK 76 hybridized with Dyneema
SK90, or Zylon HM hybridized with lower modulus Zylon). This
approach is especially useful when significant improvements in one
fiber type are offset by reduction in another critical
property.
[0065] For example, some Dyneema fibers have been drawn to a very
fine filament which improves in-plane response but introduces some
other limitations which prevent full realization of the fibers
anti-ballistic potential. Larger diameter UHMWPE fibers may have
lower properties but their thicker filaments combined with a
slightly different microstructure can combine to provide higher
overall anti-ballistic performance and protection than either one
is capable of independently. The system preferably comprises
improvement or optimization of the ballistic performance of the
monofilaments, preferably by use of fiber surface treatments,
surface functionalization, surface coatings, surface grafting
and/or deposition with one or more types or layers to optimize the
response and integration of the monofilaments to the matrix.
[0066] The system preferably further comprises engineered fiber,
preferably matrix interfacial properties by use of fiber surface
treatments, surface functionalization, surface coatings, surface
grafting and/or deposition with one or more types or layers to
optimize the response and integration of the monofilaments to the
matrix.
[0067] The system preferably further comprises incorporation of
various rate sensitive polymers and/or non-woven composites of
various fibers and polymers, preferably to produce a rate sensitive
system, preferably in strategic interlaminar and intralaminar
locations for matrix and intralaminar interfaces.
[0068] The system preferably further comprises, engineered micro
flaws in monofilaments, preferably to promote optimized localized
massive simultaneous micro-fracture of filaments, preferably to
take advantage of the inherent high strain energy release rate
thresholds related to the high Work-Energy-To-Initiate-Fracture
properties preferably combined with the high internal hysteresis
associated energy dissipation with post failure relaxation with
some anti-ballistic monofilaments such as UHMWPE and M5 fibers.
[0069] The sub-laminates may be made from a single anti-ballistic
monofilament, or multiple fibers may be combined to create a hybrid
of many types of monofilaments.
[0070] Hybridization may be at the global panel level where
sub-laminates are individually manufactured from one type of
monofilament but several sub-laminates consisting of different
types of monofilament may be used in a desired configuration. At
least one non-hybrid sub-laminate (i.e. UHMWPE, Aramid, PBO, glass)
along with sub-laminates featuring various forms and/or
combinations of fiber classes or hybridization schemes may
alternately preferably be used in a configuration.
[0071] All of the sub-laminates in a panel may be made from one
single class of fiber such as UHMWPE, Aramid, PBO, Glass, etc. if
desired. Panels made this way can be either flat or curved to
better fit the wearer. If the panels are curved, the sub-laminates
may be formed such that they nest together properly when stacked to
form the total laminate plate system.
[0072] The curved sections preferably are press formed, alternately
preferably are autoclave formed, alternately preferably are
laminate formed. Additionally, the curved sections are preferably
fabricated in one set of sub-laminates, alternately preferably are
fabricated individually and then assembled.
[0073] Upon reading the teachings of this specification, those
skilled in the art will now appreciate that, under appropriate
circumstances, considering such issues as use environment, future
technologies, cost, etc., other uses of the composite system, such
as, for example, rigid pates made from same materials systems where
flexibility is not desired, blast protection, containment of
explosive failure of rotating machinery, containment of jet engine
and other gas turbine engine compressor blade failures, sporting
good protection, crash protection, reinforcement of masonry, brick
and concrete structure and buildings to protect them from blast or
seismic damages and secondary collapse or failure, vehicle,
aircraft armor, use as a flexible "cloth" replacement for
conventional ballistic soft vests, etc., may suffice.
[0074] The flexible sub-laminate preferably makes a very high
performance option as a replacement for current vest fabrics for
flexible vests and body armor. The composite sub-laminates
preferably have superior anti-ballistic properties, and load
spreading relative to conventional cloth technologies and
preferably have the further advantage that they do not absorb
moisture and become liquid saturated, and the fiber monofilaments
are fully encapsulated and protected so they are protected from
abrasion, chaffing, flex fatigue and environmental degradation due
to sweat, fluids, chemicals, and UV or visible radiation.
[0075] In vest applications it is generally advantageous to select
the sub-laminate thickness that gives the highest degree of
anti-ballistic protection with the thinnest overall laminate
thickness, and the maximum number of the thinnest unitapes
preferably oriented in as many angular directions as is possible
consistent with cost and production throughput constraints.
Further, the use of shear thickening matrix and interlaminate
layers preferably may be used to improve impact properties.
[0076] A thin, compliant, rate-sensitive layer or layers, about
1-10 microns in thickness, preferably can be incorporated into the
sub-laminate. This layer or layers can be a viscoelastic material
with high loss factor for absorbing, damping, and dissipating
impact forces and energy release from the impact while also adding
flexibility to the sub-laminate. Strategically locating interlayers
preferably can substantially enhance load spread and energy
management by tailoring the impact impulse as was previously
discussed, and as shown in FIG. 9.
[0077] This material is especially useful for many aircraft
applications since it can be desirable to have a semi-flexible
material, for example, in the nacelle armoring the compressor
blades of the engine. The flexibility of the armor prevents
over-stiffening the nacelle, which could promote premature fatigue
of the engine support structure, but has enough rigidity during the
impact of the failed compressor blades that it can retain
structural integrity while simultaneously containing the blade
fragments.
[0078] This material is also an ideal solution for reinforcement of
masonry brick, concrete structure and buildings to protect them
from blast or seismic damages, and secondary collapse or failure by
laminating one or more sub-laminate sheets to the walls or ceilings
of the structures using an integrated gel style curing adhesive
layer or via a sprayed or brushed on toughened adhesive or a
combination of both types of bonding agents.
[0079] The material preferably can be transparent, opaque,
translucent, colored, printed or textured for decorative
architectural effects or to add camouflage, IR control or other Low
Observable finishes and textures. Additionally, the material
preferably can incorporate a weatherable outer surface layer that
has an environmental control function such as solar reflectivity or
UV blocking for insulation or energy efficiency as a secondary
feature.
[0080] Although applicant has described applicant's preferred
embodiments of this invention, it will be understood that the
broadest scope of this invention includes modifications such as
diverse shapes, sizes, and materials. Such scope is limited only by
the below claims as read in connection with the above
specification. Further, many other advantages of applicant's
invention will be apparent to those skilled in the art from the
above descriptions and the below claims.
* * * * *