Note: Descriptions are shown in the official language in which they were submitted.
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FIBER REINFORCED RESIN CONSTRUCTION AND METHOD
FOR PROVIDING BLAST ABSORPTION AND DEFLECTION
CHARACTERISTICS AND ASSOCIATED FASTENING SYSTEM UTILIZED
WITH SUCH A CONSTRUCTION
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention discloses a solid three-dimensional article
constructed of alternating, typically individually plural, layers of a lofted
glass
material alternated with a carbon Kevlar fiber. The multiple layers are held
together by a volume of a flowable resin and which, upon being cured within a
mold, exhibit consistent and enhanced elongation properties for providing
increased blast force absorption and deflection. The present invention also
discloses a process for creating a three-dimensional construction according to
the
above description, as well as a two-piece assembleable fastener for securing
together configured sheets or other assembleable components constructed
according to the above.
DESCRIPTION OF THE PRIOR ART
The prior art is well documented with various examples of ballistic or
impact/ penetration-resistant fabrics and solids, and such as which are
usually
incorporated into structural or acoustic support structures. The purpose of
such
materials is in providing a synthetic composition which is capable of being
applied to any of a number of different structural applications.
Among the examples disclosed by the prior art is U.S. Patent No.
5,545,455, issued to Prevorsek et al., which discloses an improved rigid
composite
including a plurality of fibrous layers, at least two of which are secured
together
by a securing means, and which further includes at least two adjacent paths.
The
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articles produced thereby are fiber based and are suitable for fabrication
into rigid
penetration resistant articles such as vehicle panels, spall liners for
military
vehicles and the like.
U.S. Patent No. 5,190,802, issued to Pilato, teaches improved ballistic-
resistant laminates developed by bonding alternating plies of fabric woven
from
glass or normally solid organic polymers and non-woven : scrim prepreg
impregnated with a heat curable resin. A preferred organic polymer is an
aramid
exemplified by Kevlar. A preferred heat curable resin is phenol-
formaldehyde/polyvinyl butyral blend.
U.S. Patent No. 6,562,435, issued to Brillhart, III et al., teaches a method
for forming a sheet of unidirectionally-oriented fiber strands which includes
unidirectional fibers, bonding fibers interwoven with the unidirectional
fibers to
form a fiber panel, and thermoplastic film laminating the fiber panel
therebetween. In one embodiment, a second sheet of laminated unidirectional
fibers is joined to the first sheet, and such as with the fibers running in a
second
direction as compared to the first fibers. In yet another embodiment,
individual
laminated sheets of unidirectional fibers are stitched together to form
packets of
sheets which may be used singularly or multiple packets which may be bundled
together.
U.S. Provisional Application Serial No. 2001/0053645 teaches a multi-
layered ballistic-resistant article including at least one layer of hard armor
and at
least one layer of fibrous armor composite. Each fibrous armor,composite layer
includes two or more layers of a fibrous ply, each fibrous ply having a
plurality of
unidirectional oriented fibers. Upon the layers of plies being aligned to form
the
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composite, the fibers in=adjacent fibrous plies are arranged at an acute angle
to
each other.
SUMMARY OF THE PRESENT INVENTION.
The present invention discloses a solid three-dimensional article
constructed of alternating, typically individually plural, layers of a lofted
glass
material alternated with a carbon Kevlar fiber layer. In various preferred
embodiments, each succeeding layer of material is provided with, a given
number
of sub-plies of material.
The multiple layers are held together by a volume of a flowable resin and
which, upon being cured within a mold, exhibit consistent and enhanced
elongation properties for providing increased blast force absorption and
deflection. In a preferred application, a chemical recipe associated with the
resin
mixture exhibits elongation properties consistent with those of at least the
fiber
reinforced layers and such that enhanced properties, up to twenty-five percent
corresponding to an overall volume of the material, are possible.
Additional features include the provision of a ceramic based outer layer,
for blast-resistant protection, and in addition to the provision of an
innermost
mesh screen constructed from such as wire, steel or titanium based materials,
such
further preventing inward bowing/deflection of the sandwiched layers resulting
from impact forces. It is also envisioned that appropriately configured and
ceramic covered plates of material can be constructed, such as which may
further
be interlocked together, in order to provide a blast resistant surface.
The present invention also discloses a method for creating a multiple layer
reinforced material according to the above description, as well as a two-piece
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assembleable fastener = for securing together configured sheets or other
assembleable components constructed according to the above.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made to the attached drawings, when read in
combination with the following detailed description, wherein like reference
numerals refer to like parts throughout the several views, and in which:
Fig. 1 is an exploded view of the multiple layer fiber reinforced material
according to a preferred embodiment of the present invention;
Fig. 2 is an assembled view of the reinforced material according to the first
preferred embodiment;
Fig. 3 is an enlarged sectional view of the reinforced material shown in
Fig. 2 and which better illustrates the alternating nature of the lofted glass
and
fiber reinforced layers of material;
Fig. 4 is a flow schematic of a process for creating a multiple layer fiber
reinforced material according to the present invention;
Fig. 5 is a perspective illustration of a non-planar three-dimensional article
produced according to the present invention;
Fig. 6 illustrates in sectional perspective, an overlapping lap joint edge
established between first and second sheets of material produced according to
the
present invention;
Fig. 7 illustrates an exploded view of a two-piece and frusto-conical
shaped fastener assembled in opposing fashion within aligning and likewise
frusto-conical shaped apertures defined within the overlapping lap joint edge;
Fig. 8 is an illustration of one half of a mold for producing a two-piece
fastener from an admixture of chopped glass fiber strands and resin;
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Fig. 9 is a perspeetive illustration of appropriately configured and ceramic
covered plates of material arranged in a desired fashion to providt a blast
resistant
surface; and
Fig. 10 is a further perspective illustration of a plurality of ceramic
covered and multiple layer fiber reinforced materials, such as which may
further
be configured so as to be interlocked together, and in order to provide a
blast
resistant surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to Fig. 1, an exploded illustration is shown at 10 of a
multiple layer fiber reinforced material according to a preferred embodiment
of
the present invention. The present invention is particularly suited for
producing a
blast-resistant material for incorporation into such as a floor of a vehicle
as well as
in a myriad of other applications as will be subsequently described.
The material includes a first layer, referenced generally at 12, of a lofted
glass material. In a preferred application, the lofted glass layer 12 is
actually
represented by individual sub-layers, see at 14, 16 and 18, of material which
are
stacked one upon the other.
A substratum layer of a wire mesh material 19, such as including without
limitation, steel, titanium or other suitable mesh material, may be laid into
a mold
and upon which the first layers of lofted glass 14-18, are subsequently
applied.
The wire mesh material 19 can be interchangeably used through the three
dimensional articles disclosed in the present invention, it further-being
generally
understood that the wire mesh 19 is, in a preferred variant, located proximate
an
innermost location of the article in order to prevent excessive inward bowing
or
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deflection of the finished article and. in response to forces associated with
a blast
or detonation.
A second layer of a fiber reinforced material is illustrated generally at 20
and includes individual plies 22, 24, and 26 of material, typically with each
ply
arranged in an alternating crosswise extending fashion. Three such plies are
shown, however it is understood that any plurality of plies, such as seventeen
plies, can be provided in a given overall layer 20, the same being true as to
the
number of lofted glass sub-layers 14, 16 and 18.
A third layer of a lofted glass material is further represented generally at
28 and includes additional sub-layers represented at 30, 32 and 34. As with
the
first sub-layers 14, 16 and 18 of lofted glass, any number of individual sub-
layers
of lofted glass can be incorporated according to the invention.
A volume of a flowable resin is intermixed with the layers of glass and
fiber reinforced material. In the exploded illustration of Fig. 1, the resin
volume is
referenced at 36 as a single volume applied over the sandwiched layers 12, 20
and
28. As will be further discussed, it is also envisioned that individual sub-
volumes
of resin can be applied between each succeeding layering of lofted glass and
fiber
reinforced material.
A layer or sheet of a ceramic based material 37 is illustrated in Fig. I and
which is typically placed upon the resin material 36. The ceramic material 37,
in
a preferred embodiment, defines an outermost blast-absorbing layer associated
with the completed article and can be provided as a single or multiple
overlaying
sheets. It is further understood that, with reference to the several
embodiments
disclosed throughout, the ceramic layer(s) 37 can be provided at any location
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(interior or exterior) relative to the preceding disclosed glass loft or fiber
mesh
materials.
The ceramic layer 37 typically constitutes an outermost or sacrificial layer
and which, as a result of absorbing a significant percentage of force and
shrapnel
associated with an explosive impact, shatters in the dissipation of such
forces and
to further add to the effectiveness of the article. In varying applications,
the
thickness of the ceramic layer can vary from 3/8", upwards to 6-12 inches.
Referring to the assembled and enlarged sectional views of Figs. 2 and 3,
both referenced generally at 38 any number of alternating layers of glass and
reinforced fibers can be incorporated into the reinforced material, either
with or
without the additional application of the inner steel/titanium mesh or outer
ceramic sacrificial layers illustrated in Fig. 1. In the example illustrated,
lofted
glass layers 40, 44, 48 and 52 are alternated with fiber reinforced layers 42,
46 and
50. As previously explained, any plurality of alternating layers can be
implemented according to the present invention.
In application, and referring to the application steps set forth in Fig. 4,
the
initial application of the underlaying wire/steel/titanium mesh 53 is followed
by
application of the multi-ply lofted glass layers illustrated at 54, followed
by the
sequential applications of multi-ply fiber matrix layers 56 and secondary
multi-ply
lofted glass layers 58. Additional steps include the secondary multi-ply fiber
matrix layers 60, and tertiary multi-ply lofted glass layers.
At step 64, a volume of the flowable resin is applied. In one variant, the
resin is applied in a single application within a compressible mold within
which
the layers of material are deposited. Upon the application of heat and
pressure
(step 66), the layers of material, such as referenced in Fig. 1, are
compressed (in
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one example from 6" to'/2" to'/4") into a reinforced solid, such as again
referenced
in Fig. 2. At this point, a ceramic based sheet of desired thickness may be
applied
at 67 and subsequent finishing steps including curing/trimming/sanding and
planing (see step 68) the reinforced article, as well as the application of a
surface
coating of a water-impervious material (such as a sprayable latex or acrylic)
applied to at least one surface associated with the material.
A feature of the invention is the ability of the reinforced material to
exhibit
increased elongation properties, these being determined critical to assist in
absorbing such as in particular blast forces associated with such as bombs,
heavy
objects and the like. One desired application in particular is the placement
of the
reinforced material, as forming a part of an armored vehicle wall or flooring.
Additional applications include applying the reinforced articles as plating
for ship
hulls, tanks, Humvee armor, and the like.
Tests conducted with multi-layered articles as disclosed herein yield
impressive ratings for such as compressive modulus, flexural modulus, tensile
modulus and elongation at point of rupture. In sheet form, overall weight per
thickness can vary, in certain instances it having been found that 5/8"
thickness
profile yields a weight of 6.0 lbs/sq. ft., a 3/4" profile 7.2. lbs/sq. ft.
and a 1" profile
9.6 lbs/sq. ft.
Compressing of the layers within the mold causes the flowable resin 64 to
intermix (and to substantially flow through) with each of the succeeding
lofted
glass and fiber reinforced layers. As further referenced by dashed lines 70,
72, 74,
76 and 78, intermediate applications of flowable resin may be applied between
each succeeding and alternating application of lofted glass layers and fiber
matrix
layers.
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The resin is typically applied _in a range of fifteen to eighty-five percent
by
weight in comparison to the aggregated weight of the layers of glass and fiber
reinforced materials. The resin may further be constructed of any of a
polyurethane, epoxy, polyester, bi-phenol polyester, phenol formaldehyde,
isothallic polyester, orthothallic polyester and a vinyl ester.
The elongation properties associated with the reinforced article include
typically 12% for the Kevlar strands and 8% for the carbon strands associated
with the fiber reinforced plies of material. The lofted glass layers may
further
typically possess an elongation rate in the range of 6% by volume..
In a preferred application, it is desired that the embedding resin exhibit the
same elongation percentage as at least the fibers. In order to accomplish
this, the
chemical recipe associated with the overall resin layer 64 and/or the
individual
resin layers 70, 72, 74, 76 and 78, may be individually modified to associate
different elongation properties with different layer compositions.
A desired overall elongation range associated with the three-dimensional
article is in an overall range of six to twenty-five percent corresponding to
an
overall volume of the material. For purposes of the present invention, 16%
elongation is one desired objective. This corresponds to the finished material
exhibiting a density in a range of 55-72 lbs/ft3, an impact load resistance
ranging
from 6700 psi to 8000 psi, as well as a tensile strength rating of between 155-
225
kips per square inch.
Referring further to Fig. 5, an illustration is generally represented at 80 of
a non-substantially planar shaped article, such as a helmet, produced
according to
the present invention. As illustrated, the article 80 is produced in a fashion
consistent with the disclosure of Figs. 1-4, and may include either or both a
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ceramic based (sacrificial) outermost layer in cooperation with a deformation-
retardant inner steel/titanium mesh layer. As previously discussed, other
possible
shaped articles can be produced according to the invention and which include
configured components for vehicle wheel well assemblies, rigid inserts for
such as
battle gear, and the like, it being also understood that the ceramic layer(s)
are
capable of being preconfigured in any of a variety of different shapes.
Referring now to Figs. 6-8, a fastener scheme is disclosed for securing
together such as two individual sheets 82 and 84 of reinforced material. A
problem associated with the prior art is the use of metal bolts in fastening
together
individual pieces of material and which, upon the occurrence of an explosion,
causes the bolts to fragment into shrapnel.
A solution for this problem is the production of a two-piece fastener
constructed from reinforced glass/fiber strands and which exhibit elongation
properties matching that of the associated pourable resin. The first and
second
sheets of material 82 and 84 each include a narrowed portion exhibiting an
extending and overlapping edge, see at 86 and 88, respectively, associated
with a
lap joint.
Fasteners are provided in the form of a two-piece and assembleable pin,
see at 90 and 92 in Fig. 7. The fasteners each exhibit a frusto-conical shape,
the
first fastener 90 further exhibiting an interiorly recessed inner end 94 which
mates
with an associated and exteriorly threaded portion 96 extending from an
opposing
end of the second pin 92. Aligning recesses are formed in the overlapping and
extending edges of the sheets, see at 98 and 100, for receiving, in inserting
fashion, the pin pieces 90 and 92, the same being subsequently rQtated
relative to
one another and so as to be engageably locked in place.
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As best shown in Fig. 8, a first half of a mold 102 includes a recessed
configuration corresponding to one half of a three-dimensional shape achieved
by
the finished fastener. The material content of the fastener pieces includes
reinforced chopped glass/fiber strands into which are chemically engineered
elongation properties consistent with a matching resin binder. In use, the
assembled fastener components 90 and 92 (see in Fig. 6) secures together the
sheets 82 and 84 in such a fashion that, in the instance of a collision,
fragmentation of the fastener will be consistent with an overall similar
material
content associated with the reinforced material.
Referring now to Figs. 9 and 10, it is also envisioned that appropriately
configured and ceramic covered plates of material can be constructed, such as
which may further be interlocked together, and in order to provide a blast
resistant
surface. Referring first to Fig. 9, a perspective illustration of
appropriately
configured and ceramic covered plates of material is shown at 108 and 110, and
by which the plates are arranged in a desired fashion to provide a blast
resistant
surface.
Each of the plates 108 and 110 is constructed in a fashion similar to that
disclosed in any of the preceding several embodiments, and which includes an
outer ceramic layer(s), in cooperation with a desired admixture of lofted
glass,
resin, and fibrous sheet materials, with the further optional addition of an
innermost steel/titanium deflection retardant mesh.
Figure 10 is a further perspective illustration of a plurality of ceramic
covered and multiple layer fiber reinforced materials, and such as which may
further be configured as individual components 112, 114, 116, et seq., so as
to be
interlocked together, and in order to provide a blast resistant surface. In
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particular, each of the assembleable.components may include a suitable lip and
channel arrangement, see as illustrated in alternating fashion by channel 118
extending along an edge of component 112, opposite lip 120 and channel 122
edges associated with component 114, engaging lip 124 of component 116, et
seq.
As stated previously, the shaping of the individual components is not
limited to any configuration, it being understood that any suitable shape can
be
established by each of the aligning and engaging components, and through the
application of forming processes associated with the present invention. Such
includes arcuate and curved shapes for creating outer surface protection of
arcuate
surface areas associated with ship hulls, tanks, etc., and in addition to
substantially
planar and interengaging sheets for deck and floor armor protection.
A method for creating a multiple layer reinforced material, corresponding
to the above-referenced assembly, includes the steps of applying a first layer
of a
lofted glass material, applying a second layer of a fiber reinforced material
over
the glass material, applying a further layer of lofted glass material over the
fiber
reinforced material. Additional steps include depositing a volume of a resin
syrup
upon the layers of glass material and the fiber reinforced mate,rial, applying
a
combination of heat and pressure to the layers of materials, and providing at
least
one of curing, trimming, sanding and planning operations, in succeeding order,
to
create a finished product.
Additional steps include applying multiple individual plies of material
associated with at least one of the lofted glass and said fiber reinforced
materials,
applying a plurality of alternating layers of lofted glass and fiber
reinforced
material, applying the multiple individual plies of material in crosswise
extending
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fashion, and applying a water impervious material to at least one surface
associated with the material.
Yet additional steps include applying heat and pressure to compress the
layered material from a first overall thickness to a second reduced thickness,
depositing a sub-volume of resin syrup between each succeeding layer of lofted
glass and fiber reinforced materials, and applying a resin material selected
from
the group including a polyurethane, epoxy, polyester, bi-phenol polyester,
phenol
formaldehyde, isothallic polyester, orthothallic polyester and a vinyl ester.
Other steps include applying the resin in a range of fifteen to eighty-five
percent by weight in comparison to the layers of lofted glass and fiber
reinforced
material, and varying a chemical composition of the resin syrup to exhibit
elongation properties similar to those associated with at least the fiber
reinforced
material. Additional steps include the step of fastening first and second
sheets of
material, each exhibiting an extending and overlapping edge associated with a
lap
joint, the step of forming aligning recesses in the overlapping edges
associated
with the first and second sheets of material, and further comprising the step
of
inserting a two-piece and assembleable pin within the aligning recesses.
Finally,
the step of forming each of the assembleable pin pieces from a reinforced
chopped
glass fiber is taught, each exhibiting a frusto-conical shape qorresponding to
frusto-conical shaped recesses defined in the overlapping lap joint edges.
Having described my invention, additional preferred embodiments will
become apparent to those skilled in the art to which it pertains and without
deviating from the scope of the appended claims.
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