U.S. patent number 3,722,355 [Application Number 04/477,671] was granted by the patent office on 1973-03-27 for lightweight armor material.
This patent grant is currently assigned to Aerojet-General Corporation. Invention is credited to Harry A. King.
United States Patent |
3,722,355 |
King |
March 27, 1973 |
LIGHTWEIGHT ARMOR MATERIAL
Abstract
This disclosure concerns a lightweight armor material which
includes a woven fabric of glass and nylon fibers, wherein the
individual glass fibers are interlaced with individual nylon fibers
so as to provide an interwoven relationship between the glass
fibers and the nylon fibers. A woven fabric of this character is
especially suitable for use in body armor and may be employed in
multiple layers arranged in superposed relation, either with or
without a binding resin, to provide a structural material affording
protection against a high energy particle, such as a projectile or
fragments therefrom. The structural material has a high resistance
to the penetration of a high energy particle in relation to its
weight which is superior to the penetration resistance of a
comparable structure of the same weight but including woven fabric
layers of either glass fibers or nylon fibers alone. A hard outer
surface plate of a ceramic material may be included as a component
of the structural material in one embodiment thereof, enabling the
structural material to successfully withstand the direct impact of
certain types of projectiles thereagainst by preventing the
penetration of these projectiles and thereby protecting personnel
from injury and/or equipment from damage.
Inventors: |
King; Harry A. (Covina,
CA) |
Assignee: |
Aerojet-General Corporation (El
Monte, CA)
|
Family
ID: |
23896860 |
Appl.
No.: |
04/477,671 |
Filed: |
August 3, 1965 |
Current U.S.
Class: |
89/36.02; 2/2.5;
442/212; 428/911 |
Current CPC
Class: |
F41H
1/02 (20130101); F41H 5/0435 (20130101); A41D
31/245 (20190201); Y10T 442/3252 (20150401); Y10S
428/911 (20130101) |
Current International
Class: |
A41D
31/00 (20060101); F41H 5/04 (20060101); F41H
5/00 (20060101); F41H 1/00 (20060101); F41H
1/02 (20060101); F41h 001/02 (); F41h 005/04 () |
Field of
Search: |
;89/36
;161/404,155,197,91,92,93 ;2/2.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bentley; Stephen C.
Claims
I claim:
1. A lightweight impact and delamination resistant, non-metallic
armor member for providing protection against high energy
particles, such as projectiles, said armor member comprising:
an outer surface layer of material having a hardness and
compressive strength substantially equal to or greater than that of
hard steel,
a plurality of layers of fibrous material arranged in stacked
superposed relation behind said outer surface layer,
each of said layers of fibrous material comprising a woven fabric
of glass and nylon fibers, individual glass fibers in each woven
fabric layer being interlaced with individual nylon fibers in the
same woven fabric layer so as to provide an interwoven relationship
between the glass fibers and the nylon fibers in the same fabric
layer, and
each of said plurality of layers of woven fabric being impregnated
with resin so as to be bonded together with said outer surface
layer to define a laminated composite plate-like structure having a
high resistance to the penetration of a high energy particle in
relation to its weight which is superior to the penetration
resistance of a comparable structure of the same weight but
including woven fabric layers of either glass fibers or nylon
fibers alone.
2. A lightweight impact and delamination resistant, non-metallic
armor member as set forth in claim 1 wherein said glass fibers are
roving material.
3. A lightweight impact and delamination resistant, non-metallic
armor member as set forth in claim 1 wherein said nylon fibers have
lower unit weight than said glass fibers.
4. An armor material for providing protection against high energy
particles, such a projectiles, said armor material comprising:
an outer surface layer of material having a hardness and
compressive strength substantially equal to or greater than that of
hard steel,
a woven fabric of glass and nylon fibers,
individual glass fibers in said woven fabric being interlaced with
individual nylon fibers in said woven fabric so as to provide an
interwoven relationship between the glass fibers and the nylon
fibers in said woven fabric, and
a resinous material coating said glass and nylon fibers and filling
the interstices among them so as to form a semistructural fabric
material bonded to said outer surface layer and having a high
resistance to the penetration of a high energy particle in relation
to its weight which is superior to the penetration resistance of a
comparable structure of the same weight but including a woven
fabric comprising either glass fibers or nylon fibers alone.
5. A lightweight impact and delamination resistant, non-metallic
armor member for providing protection against high energy
particles, such as projectiles, said armor member comprising:
an outer surface layer of material having a hardness and
compressive strength substantially equal to or greater than that of
hard steel,
a plurality of layers of fibrous material arranged in stacked
superposed relation behind said outer surface layer,
each of said layers of fibrous material comprising a woven fabric
of glass and nylon fibers, individual glass fibers in each woven
fabric layer being interlaced with individual nylon fibers in the
same woven fabric layer so as to provide an interwoven relationship
between the glass fibers and the nylon fibers in the same fabric
layer,
a resinuous material coating said glass and nylon fibers of each of
said layers of woven fabric and filling the interstices among said
fibers so as to bond said plurality of layers of woven fabric
together with said outer surface layer,
the relative proportions of glass and nylon fibers in each of said
layers of woven fabric lying between 90 parts of glass to 10 parts
of nylon and 10 parts of glass to 90 parts of nylon, by weight,
and
said outer surface layer and said plurality of layers of woven
fabric bonded together therewith defining a laminated composite
plate-like structure having a high resistance to the penetration of
a high energy particle in relation to its weight which is superior
to the penetration resistance of a comparable structure of the same
weight but including woven fabric layers of either glass fibers or
nylon fibers alone.
6. A lightweight impact and delamination resistant, non-metallic
armor member as set forth in claim 5 wherein the material of said
outer surface layer has a compressive strength substantially equal
to or above 100,000 psi and a hardness substantially equal to or
above Rockwell C-50.
7. A lightweight impact and delamination resistant, non-metallic
armor member as set forth in claim 5, wherein the material of said
outer surface layer is selected from the group consisting of glass,
alumina, boron carbide, or silicon carbide.
Description
This invention relates to a non-metallic armor material formed to
provide exceptional impact resistance, thereby affording an
exceptional penetration resistance-to-weight ratio.
The present invention contemplates the provision of armor plate
formed of the novel material which, however, may be utilized for
other purposes. The following description of the application of the
material to the production of armor is given by way of illustration
only.
Body armor has previously been formed of reinforced plastic
materials, such as low pressure glass-polyester laminates. Such
armor, however, is subject to delamination about the area of
missile impact with consequent reduction in strength of the armor,
and in effectiveness in case of a second impact.
It is therefore an object of this invention to provide a composite
material suitable for use as armor which is more efficient on a
weight basis in stopping high velocity fragmentation projectiles or
ogive shaped projectiles, than any of the individual materials of
which it is composed, or any other material generally accepted for
this use.
Another object of this invention is to provide a non-metallic
laminated material suited for use both as body armor and for armor
purposes in aircraft, personnel carriers and the like.
Still further objects of the present invention will become more
fully apparent as the description proceeds when taken in connection
with the accompanying drawings, in which:
FIG. 1 is a greatly enlarged plan view of a woven fabric comprising
a lightweight armor material and including interlaced glass and
nylon fibers in accordance with the present invention;
FIG. 2 is a sectional view of a laminated armor member including a
plurality of layers of woven fabric of the type illustrated in FIG.
1 impregnated with a resin and bonded together into a composite
laminate structure;
FIG. 3 is a perspective view of body armor made of woven fabric of
the type illustrated in FIG. 1;
FIG. 4 is a perspective view, partially broken away, showing a
laminated armor member having a hard outer surface plate as a
component thereof in accordance with the present invention; and
FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4.
A great deal of time and effort has been expended on the
development and determination of the lightest weight armor for use
against fragmentation type projectiles. One of the most widely used
and successful to date is Doron or Doron II, a laminate composed of
unidirectional glass fabric such as 143 cloth and a polyester resin
in a fairly low concentration. Notably higher weights than for
Doron are required to stop the same projectile under the same
conditions with nylon fabric, either bonded or unbonded; steel;
aluminum; or titanium armor alloy, as will be shown
hereinafter.
I have found that by interweaving glass and nylon fibers into one
fabric, a substantially more projectile-resistant material results
which has been found to be better than a fabric woven of either
glass fibers or nylon fibers alone. Thus, FIG. 1 shows a woven
fabric 10 constructed in accordance with the present invention so
as to include individual glass fibers 11 interlaced with individual
nylon fibers 12 to provide an interwoven relationship between the
glass fibers 11 and the nylon fibers 12 comprising the woven fabric
10. In one embodiment, as shown in FIG. 2, a series of woven fabric
layers 10 in which glass fibers 11 and tough, flexible fibers 12,
such as nylon, are interwoven with the glass fibers 11, is
impregnated with resin 13 and bonded into a multi-ply laminate 14.
The superior performance of this laminate member 14 as an armor
material in comparison to that of comparable laminate members
employing resin-impregnated fabric layers woven of only, glass or
nylon fibers alone is totally unexpected since it would normally be
thought that the test results of the laminate member 14 of FIG. 2
would lie somewhere between the test results obtained from laminate
members respective employing woven glass fabric layers and woven
nylon fabric layers. While the theoretical aspects of the woven
fabric 10 of FIG. 1 and the laminate member 14 of FIG. 2 have not
been fully developed, it is believed that there is an interaction
between the two types of fibers comprising the woven fabric 10. The
glass fiber 11 is thought to serve the function of the strong
member and preferably is composed of roving, rather than twisted
fibers, while the lighter-weight nylon fiber 12 is believed to
function as both a supporting structure and elongating or
stretching member. Thus, both high strength and stiffness and high
elongation are obtained in one interwoven material. The optimum
ratio of glass to nylon has been determined to lie within the range
from about 90 parts glass and 10 parts nylon to 10 parts glass and
90 parts nylon, by weight.
The resin binder 13 may be a cured polyester or epoxy resin or
preferably a rubber-phenolic resin so that resin elongation,
between 10 and 400 percent is obtained, permitting the nylon -glass
fabric 10 to move further without delamination. These resins are
applied to the woven fabric layers in an uncured state, after which
the impregnated fabric layers are combined to make the desired
configuration and thickness, and then cured in that state.
Comparative date demonstrating the notably higher weights required
for other armor materials to stop the same projectile under the
same conditions is shown in tabular form below.
TABLE I
APPROXIMATE EQUIVALENT WEIGHT FOR A V.sub.50 OF 1600 FT/SEC FOR
0.50 CAL. FRAGMENT SIMULATOR AT 0.degree. OBLIQUITY
Material (1bs/sq ft) New nylon-glass, satin weave, about 50/50
volume basis, with resin binder 5.6 Doron II (unidirectional (Style
143) glass with resin binder) 6.1 All nylon fabric, with resin
binder 6.3 2024 T-4 Aluminum 7.7 Titanium (6al. 4V) 6.4 Steel,
rolled homogenous 7.2
TABLE II
APPROXIMATE EQUIVALENT WEIGHT FOR A V.sub.50 OF 1300 FT/SEC FOR
0.50 CAL. FRAGMENT SIMULATOR AT 0.degree. OBLIQUITY
Material (1bs/sq ft) Doron II 4.5 New nylon-glass, square weave,
about 50/50 volume basis, with resin binder 3.8
The armor produced by this invention has superior penetration
resistance to fragments-per-unit weight of armor, and resists
delamination under missile impact. It is especially suitable for
use in body armor, although it can find use in the protection of
personnel carriers or aircraft such as helicopters, for example,
which may be, and commonly are, required to operate at low
altitude, bringing them within range of rifle fire from the
ground.
However, this combination of fibers, may also be used by itself,
i.e., without a binding resin, so that it can follow a moving
contour such as a body. Thus, FIG. 3 illustrates body armor 15 made
of layers of the woven fabric 10 of FIG. 1. When the binding resin
13 is used with the layers of woven fabric 10, the resulting
laminate member 14 of FIG. 2 is rigid and semi-structural. The
layers of woven fabric 10 may also be combined with a very hard
surface plate 16, such as alumina, a hard ceramic material, as
shown in FIGS. 4 and 5. When used without the hard surface plate
16, the laminate member 14 is effective in stopping metal
fragments, as from the air burst of an anti-aircraft weapon. With
the hard outer surface 16 of alumina, the composite laminate member
14' of FIGS. 4 and 5 is effective in stopping ball and armor
piercing bullets, such as .30 cal. and 7.62 mm rifle bullets, even
when such projectiles directly import thereagainst. In all three
embodiments, this woven fabric 10 has been proven to be more
effective as an armor material from a weight standpoint than either
an all glass fabric or an all nylon fabric.
While I have designated alumina as the material of the outer
surface plate 16 in the embodiment illustrated in FIGS. 4 and 5,
any material having a hardness and compressive strength
substantially equal to or greater than that for hard steel will
also serve. The ideal material for the outer surface plate 16 has
compressive strengths above 100,000 psi and hardnesses above
Rockwell C-50. Ceramics type materials, such as glass, aluminum
oxide (alumina), boron carbide and silicon carbide or the like are
ideal.
The described use of the woven fabric 10 for armor material enables
a very considerable saving in weight to be obtained in providing
protective armor for specific purposes. Preferred embodiments of
the invention have been described by way of example, but should not
be considered as limiting the invention since various changes in
the described embodiments may be made by those skilled in the art
without departing from the scope of the invention as defined by the
appended claims.
* * * * *