U.S. patent application number 13/796080 was filed with the patent office on 2014-09-18 for transparent impact resistant system.
This patent application is currently assigned to INTERNATIONAL CITY TECHNOLOGIES LLC. The applicant listed for this patent is INTERNATIONAL CITY TECHNOLOGIES LLC. Invention is credited to Labros Hydras.
Application Number | 20140260932 13/796080 |
Document ID | / |
Family ID | 51521457 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140260932 |
Kind Code |
A1 |
Hydras; Labros |
September 18, 2014 |
Transparent Impact Resistant System
Abstract
A transparent impact resistant system, that includes a sheet of
aluminum oxynitride, a sheet of single-crystal aluminum oxide and
an interlayer attached between the aluminum oxynitride and the
single-crystal aluminum oxide. Additional sheets of each material
can be added depending on the threat level. The interlayer may
include an energy absorption layer and a reinforcement layer.
Inventors: |
Hydras; Labros; (Potomac,
MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTERNATIONAL CITY TECHNOLOGIES LLC; |
|
|
US |
|
|
Assignee: |
INTERNATIONAL CITY TECHNOLOGIES
LLC
Potomac
MD
|
Family ID: |
51521457 |
Appl. No.: |
13/796080 |
Filed: |
March 12, 2013 |
Current U.S.
Class: |
89/36.02 |
Current CPC
Class: |
F41H 5/0407 20130101;
F41H 5/0428 20130101 |
Class at
Publication: |
89/36.02 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
1. A transparent impact resistant system, comprising: at least one
sheet of aluminum oxynitride; at least one sheet of single-crystal
aluminum oxide; and at least one interlayer attached between the at
least one sheet of aluminum oxynitride and the at least one sheet
of single-crystal aluminum oxide.
2. The transparent laminate of claim 1, wherein the interlayer
comprises an energy absorption layer.
3. The transparent impact resistant system of claim 2, wherein the
interlayer further comprises a reinforcement layer.
4. The transparent impact resistant system of claim 2, wherein the
interlayer further comprises a waveguide.
5. The transparent impact resistant system of claim 4, wherein the
waveguide comprises a spinel element.
6. The transparent impact resistant system of claim 4, wherein the
waveguide comprises a single sheet of aluminum oxynitride.
7. The transparent impact resistant system of claim 4, wherein the
waveguide comprises a single sheet of single-crystal aluminum
oxide.
8. The transparent impact resistant system of claim 1, wherein the
interlayer comprises polyvinyl butyral.
9. The transparent impact resistant system of claim 1, wherein the
interlayer comprises a polymer.
10. The transparent impact resistant system of claim 9, wherein the
polymer layer comprises an ionoplast layer.
11. The transparent impact resistant system of claim 1, wherein the
at least one sheet of aluminum oxynitride is positioned on the side
of a potential impact relative to the at least one sheet of
single-crystal aluminum oxide.
12. A transparent impact resistant system, comprising: a first
rigid layer; a second rigid layer; and at least one interlayer
attached between the first rigid layer and the second rigid layer,
wherein the interlayer comprises an energy absorption layer and a
waveguide.
13. The transparent impact resistant system of claim 12, wherein
the waveguide comprises a spinel element.
14. The transparent impact resistant system of claim 12, wherein
the waveguide comprises a single sheet of aluminum oxynitride.
15. The transparent impact resistant system of claim 12, wherein
the waveguide comprises a single sheet of single-crystal aluminum
oxide.
16. The transparent impact resistant system of claim 12, wherein
the energy absorption layer comprises polyvinyl butyral.
17. The transparent impact resistant system of claim 12, wherein
the energy absorption layer comprises a polymer.
18. The transparent impact resistant system of claim 12, wherein
the first rigid layer comprises at least one sheet of aluminum
oxynitride positioned on a side of a potential impact.
19. The transparent impact resistant system of claim 12, wherein
the second rigid layer comprises at least one sheet of
single-crystal aluminum oxide.
20. A transparent impact resistant system, comprising: a first
rigid layer; a second rigid layer; and at least one interlayer
attached between the first rigid layer and the second rigid layer,
wherein the interlayer comprises an energy absorption layer and a
reinforcement layer.
21. The transparent impact resistant system of claim 20, wherein
the first rigid layer comprises a first spinel element and the
second rigid layer comprises a second spinel element.
22. The transparent impact resistant system of claim 20, wherein a
thickness of the reinforcement layer is less than 0.05% of a
thickness of the interlayer.
23. The transparent impact resistant system of claim 20, wherein
the reinforcement layer comprises a spinel element.
Description
FIELD OF THE INVENTION
[0001] The field of invention related to armor systems and, more
particular to bullet-proof windows.
BACKGROUND
[0002] This purpose of this invention is to produce a new and
improved transparent impact resistant system (TIRS) which is
tailored primarily for bullet-proof windows or other impact
resistant applications. Traditional bullet-proof window panes are
of large areal densities that can defeat mainly small to medium
caliber bullets. Larger caliber bullets require traditional
bullet-proof window pane thicknesses of the order of 10.2 to 12.7
cm (4.0 to 5.0 in.).
[0003] Ballistic glass sections are typically laminated glass
panels interconnected with Bucalite, polyvinyl butyral (PVB),
interlayers. The distribution, arrangement, individual laminae
thicknesses, and overall section thickness dictate the performance
of the sections against various Underwriters Laboratory UL-752
(UL-752) defined ballistic levels. These levels range from small
caliber bullets, such as the 9 mm (Level I) threat, to large
caliber, such as M-14 or M-16 multiple bullets (corresponding to
Levels VII and VIII, respectively), as well as the .50 caliber
(Level X). The state-of-the-art of such a window section
incorporates a combination of improved glass plies of various
strengths, connected using transparent interlayers, such as
polyvinyl butyral (PVB) or Ionoplast (IonP). The glass plies can
also be of variable thermal characteristics, depending on their
environmental application.
[0004] There are several problems associated with the traditional
bullet-proof windows. The main problem is the actual size of the
composite pane that is required to arrest a high kinetic energy
(K.E.), high momentum ammunition, such as the 7.62-mm or, even
worse, the .50 caliber. The brittle nature of the silicon oxide
based glass section and the poor absorption and distribution of the
initial energy of the impacting entity, because of development of
"infinite stresses" in the vicinity of its tip, makes the typical
bulletproof glass impractical for applications requiring defeat of
.50 caliber ammunition due to weight restrictions.
[0005] In addition, the use of several layers of glass (anywhere
from twelve to eighteen) in conjunction with the use of IonP
interlayers result in a section that is not clear and,
consequently, the term transparent loses its true sense.
[0006] Variations of the bullet-proof window panes may also use
single crystal layers of spinels or aluminum oxinitride
((AlN).sub.x.(Al.sub.2O.sub.3).sub.1-x, where 0.30<x<0.38),
also known as ALON, placed externally, on the side of impact, fused
to one or more internal glass layers via PVB, and terminating with
a polycarbonate layer on the side opposite from the impacting
surface.
[0007] Both variations of bullet-proof glass, described above, may
resist the full penetration of the 7.62 mm, the medium size
ammunition, but they still require significant thickness to defeat
the .50 caliber threat.
SUMMARY
[0008] A transparent impact resistant system (TIRS) may be used as
an improved practical, transparent, bullet-proof composite section
using newly developed and already field tested materials. The
combination of these materials into a new composite section results
in a (TIRS) that is, at the most, 51 mm (2.0 in.) and it can defeat
a .50-caliber, 48.6 g (750 grains) average mass* bullet from a
standoff of 4.57 m (15 ft). The new bullet-proof system can be
modified to resist the full penetration of a .50 caliber bullet
with as little as 3.5 to 5.1 cm (1.4 to 2.0 in.). The TIRS also has
more general applications to produce impact resistant materials.
*The mass of the .50 caliber ammunition can vary by as much as 10 g
(155 grains)
[0009] In one general aspect, a transparent impact resistant system
includes aluminum oxynitride, single-crystal aluminum oxide, and at
least one interlayer attached between the at least one sheet of
aluminum oxynitride and the at least one sheet of single-crystal
aluminum oxide.
[0010] Embodiments may include one or more of the following
features. For example, the interlayer may have an energy absorption
layer, a reinforcement layer and/or a waveguide.
[0011] The waveguide may be a single sheet of aluminum oxinitride,
single sheet of single-crystal aluminum oxide or another type of
spinel element. The energy absorption layer may be polyvinyl
butyral, a polymer or an ionoplast layer.
[0012] In one of the embodiments, the aluminum oxynitride is
positioned on the side of a potential impact relative to the
single-crystal aluminum oxide.
[0013] In another general aspect, a transparent impact resistant
system includes a first rigid layer, a second rigid layer, and at
least one interlayer attached between the first rigid layer and the
second rigid layer. The interlayer may have an energy absorption
layer and a waveguide.
[0014] The waveguide may be a spinel element such as a single sheet
of aluminum oxynitride or a single sheet of single-crystal aluminum
oxide. The energy absorption layer may include polyvinyl butyral or
a polymer.
[0015] The first rigid layer may be a sheet of aluminum oxynitride
positioned on a side of a potential impact. The second rigid layer
may be a sheet of single-crystal aluminum oxide.
[0016] In still another general aspect, a transparent impact
resistant system includes a first rigid layer, a second rigid
layer, and an interlayer attached between the first rigid layer and
the second rigid layer. The interlayer has an energy absorption
layer and a reinforcement layer and may also include one or more of
the above features.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1a and 1b--Impact Tests for Configuration "B", Vo=4.03
km/s, D=6.35 mm 1a) Initial Setup and 1b) Late Time Response.
[0018] FIG. 2--Graph of Kinetic Energy vs. Time Variation for
Configuration "B" with Vo=4.03 km/s and D=6.35 mm.
[0019] FIGS. 3a and 3b--Impact Tests for Configuration "B", Vo=3.90
km/s, D=3.97 mm 3a) Initial Setup and 3b) Late Time Response.
[0020] FIGS. 4a and 4b Graphs of 4a) Projectile's C. G. Position
and 4b) K.E. vs. Time Variation for Configuration "B" with Vo=3.90
km/s and D=3.97 mm.
[0021] FIG. 5--Impact Test of Late Time Response for Configuration
"C", Vo=2.67 km/s, D=6.35 mm.
[0022] FIG. 6--Graph of Projectile's K.E. vs. Time Variation for
Configuration "C" with Vo=2.67 km/s and D=6.35 mm.
[0023] FIGS. 7a and 7b--Graphs of Projectile's C.G.'s a) Position
and b) Velocity vs. Time Variation for Configuration "C" with
Vo=2.67 km/s and D=6.35 mm.
[0024] FIG. 8--Impact Test of Late Time Response for Configuration
"C", Vo=2.90 km/s, D=3.97 mm.
[0025] FIG. 9--Graph of Projectile's K.E. vs. Time Variation for
Configuration "C" with Vo=2.90 km/s and D=3.97 mm.
[0026] FIGS. 10a-10d--Tests of Six-Ply Arrangement Subjected to
7.62-mm Impacting Projectile, V.sub.0 of 875 m/s, for Estimating
V.sub.50 10a) Original Configuration, 10b) Late Time Response, 10c)
K.E. Degradation, and 10d) Penetrator's Select Velocity Response
Along Points on its Axis of Symmetry.
[0027] FIGS. 11a-11d--Tests for Three-Ply Arrangement for
Estimating V.sub.50 11a) Original Configuration, 11b) Late Time
Response, 11c) K.E. Degradation, and 11d) Penetrator's Select
Position Along Axis of Symmetry Velocity Response subjected to the
7.62-mm impacting projectile with V.sub.0 of 791 m/s.
[0028] FIG. 12--Close-up of Numerical Model (Slice through the
Vertical Axis).
[0029] FIG. 13--7.62-mm Slug Select Station Position Variation with
Time.
[0030] FIG. 14--Resting Position of the 7.62-mm Ammunition
Slug.
[0031] FIGS. 15a and 15b--Final Configuration and Penetration
Levels of the 7.62-mm Slug Impacting 23-mm (15a) and 33-mm (15b)
TIRS Sections, respectively.
[0032] FIG. 16--Numerical Setup of the .50 Caliber Example 2
Case.
[0033] FIGS. 17a and 17b--Final Configuration and Penetration
Levels (17a) and Select Bullet Station Position Variation with Time
(17b) for the .50 Caliber Impacting a 40.5-mm TIRS Section.
[0034] FIGS. 18a-18d--18a) Initial (t=0) and 18b) Rest (t>240
ms) Configurations, Select Bullet Station 18c) Position, and 18d)
Velocity Variation with Time for the 46 g, .50 Caliber Impacting a
42.0-mm Section.
[0035] FIGS. 19a-19d--19a) Rest (t>260 ms) Configuration, 19b)
Select Bullet Station Velocity Variation with Time, 19c) Kinetic
Energy Dissipation of Ammunition, and 19d) Select Bullet Position
Variation with Time for the 52 g, .50 Caliber Impacting a 42.0-mm
TIRS Section.
[0036] FIGS. 20a-20d--20a) Initial and 20b) Final Configurations,
20c) Select Bullet Station Velocity Histories, and 20d) Kinetic
Energy Dissipation of Ammunition for the Upper Bound UL-752, Level
IX.
[0037] FIGS. 21a-21d--21a) Initial and 21b) Final Configurations,
21c) Select Bullet Station Velocity Histories, and 21d) Kinetic
Energy Dissipation of Ammunition for the Upper Bound UL-752, Level
X.
DETAILED DESCRIPTION
[0038] The overall approach was differentiated into four tasks:
[0039] 1. Collect already existing experimental data that report
the behavior of laminated glass units (LGU's) under various impact
environments. These include medium caliber ammunition, such as the
7.62-mm ballistic, impacting multilayered LGU's; [0040] 2. Conduct
numerical simulations using explicit finite element analysis (FEA)
codes, such as the free licensed software FreeFEM++, in order to
compare the experimental with the numerical data; [0041] 3.
Calibrate the numerical models to match the experimental results in
the event that gross differences exist between the two; and [0042]
4. Once the numerical work is completed, employ FEA techniques to
simulate new TIRS sections using combinations of ALON, sapphire
(Al.sub.2O.sub.3), IonP, polycarbonate, and/or a sheet of
alkali-aluminosilicate glass (AAL) as the materials under
consideration.
Task 1: Collection of Already Existing Experimental Data.
[0043] Two sets of data were collected from the open literature.
The reference for the first set of data is: [0044] Ha, Y, Guang, G,
Chi, R., Pang, B., "Experimental and Numerical Studies of Laminated
Glass Subject to Hypervelocity Impact," Journal of Explosion and
Shock Waves, May, 2005.
[0045] A total of seventeen impact tests were presented in this
paper. Of these, only nine employed three distinct plies of glass
comprising the LGU's. The other eight tests were impacts on either
stacks of glass plies with no interlayer connection or they
involved more than three plies. Moreover, some of the experimental
setups were duplicates to ensure repeatability of the results. The
remaining experimental setups involved two different configurations
of LGU's. One setup uses three 12-mm glass plies that are connected
using 2.times.0.76-mm PVB interlayers. This arrangement is referred
to a configuration "B". A second setup, uses a 12-mm glass ply
sandwiched between two 5-mm glass plies. All plies are
interconnected using two 0.76-mm PVB interlayers. This arrangement
is referred to as configuration "C". In addition, two different
size of impacting entities were used, a 6.35-mm and a 3.97-mm
spherical ball made of 2017-T4 aluminum alloy.
[0046] Four representative experimental setups were chosen to be
numerically simulated, namely: [0047] 1. Configuration "B" with an
initial impact velocity of 4.03 km/s, using the 6.35-mm diameter
spherical impactor. [0048] 2. Configuration "B" with an initial
impact velocity of 3.90 km/s, using the 3.97-mm diameter spherical
impactor. [0049] 3. Configuration "C" with an initial impact
velocity of 2.67 km/s, using the 6.35-mm diameter spherical
impactor. [0050] 4. Configuration "C" with an initial impact
velocity of 2.90 km/s, using the 3.97-mm diameter spherical
impactor.
[0051] All simulated setups assume normal impact of the projectile
onto the target.
[0052] The second set of experimental data gathered from the open
literature is from the following reference: [0053] Richards, M.,
Clegg, R., and Howlett, S. "Ballistic Performance Assessment of
Glass Laminates Through Experimental and Numerical Investigation,"
The 18th International Symposium and Exhibition on Ballistics San
Antonio, Tex., 1999.
[0054] Three experiments were reported in this reference. All of
the experiments used the 7.62 mm.times.51 mm NATO ball round as the
standard projectile. The first experiment incorporated a monolithic
glass panel. The second section was a LGU's made of three, 6-mm
glass plies which were interconnected via polyurethane interlayers.
The third section's makeup consisted of six, 3-mm glass plies also
interconnected using polyurethane interlayers. All three assemblies
were attached to a 6-mm polycarbonate backing material. The
ballistic limits, V.sub.50 , values were reported in each case. The
V.sub.50 ballistic limit is equivalent to a 50% probability of the
projectile penetrating the target.
[0055] Two experimental setups were chosen to be numerically
simulated from this set of experiments, namely: [0056] 1. The six,
3-mm LGU subjected to the 7.62-mm impacting projectile with an
initial velocity of 875 m/s. [0057] 2. The three, 6-mm LGU
subjected to the 7.62-mm impacting projectile with an initial
velocity of 790 m/s.
[0058] Both experimental and the numerical setups assume normal
impact of the projectile with respect to the target.
Task 2: Numerical Simulations Using Explicit Codes. Comparison of
Experimental Results With Numerical Output.
[0059] The paper by Ha et al. provides detailed description of the
LGU's constituent materials and their mechanical properties. The
numerical models, built herewith, used the constitutive material
parameters provided by the authors. Explicit modeling of the
spherical projectile and the LGU's was carried out.
Configuration "B", Velocity=3.9 km/s, with 3.97-mm Diameter
Spherical Projectile
[0060] FIGS. 1a and 1b show the 2-D representation of the FEA
model. Each of the material components was numerically represented.
The overall thickness of the section (target) is 37.56 mm. The
spherical projectile was assigned the hypervelocity value of 3.9
km/s.
[0061] As shown in FIG. 2 the projectile is converted into a slug
and a total penetration of slightly less than 10 mm is achieved.
This value is in close agreement with that provided by the
experimental outcome, which was reported as being 9.8 mm.
[0062] The majority of the K.E. of the projectile dissipates within
the first 0.01 ms (FIGS. 3a and 3b) and reaches zero within the
first 0.025 ms.
Configuration "B" with an Initial Impact Velocity of 4.04 km/s,
Using the 6.35-mm Diameter Spherical Impactor.
[0063] The 37.56-mm section is subjected to 4.04 km/s impact of a
6.35-mm diameter sphere. The initial and late time response of the
arrangement are shown in FIGS. 3a and 3b, respectively. A trace at
the center of gravity (c.g.) of the impacting sphere reveals the
degradation of the initial velocity--see FIG. 4a--until it
completely disappears. The K.E. dissipation plot is also provided
in FIG. 4b. It is notable that despite the fact that the initial
K.E. of this experiment is substantially less than that of the one
reported in the previous section (the relative ratio of their
K.E.'s is 7 to 30), yet the relative perforation of the two is,
approximately, the same (1:1). This fact is verified both
numerically and experimentally.
Configuration "C" with an Initial Impact Velocity of 2.67 km/s,
Using the 6.35-mm Diameter Spherical Impactor.
[0064] The 23.56-mm thick LGU is impacted with a 6.35-mm in
diameter spherical projectile, traveling at 2.67 km/s. The late
time stage of the simulation is shown in FIG. 5. The K.E.'s
variation of the projectile is shown in FIG. 6. It can be seen from
this figure that the majority of the K.E. is dissipated within the
first 7.5.times.10.sup.-3 ms. FIG. 7a shows the relative position
of the c.g. of the projectile during the course of the numerical
simulation as well as that of the velocity in FIG. 7b. The Front
face perforation was reported as 8.0 mm by Ha et al. The simulated
perforation is 7.98 mm.
Configuration "C" with an Initial Impact Velocity of 2.90 km/s,
Using the 3.37-mm Diameter Spherical Impactor.
[0065] The late response of the 23.56-mm thick LGU subjected to the
3.37-mm diameter spherical projectile with an initial velocity of
2.90 km/s is shown in FIG. 8. The maximum perforation is restricted
to within the first ply of glass (impact side) and the first
interlayer for a total of 5.4 mm which is exactly the same as the
experimental result reported for this particular case. FIG. 9 shows
the K.E. associated with the projectile and its degradation over
time.
The Six, 3-mm LGU Subjected to the 7.62-mm Impacting Projectile
with am Initial Velocity of 875 m/s.
[0066] The original configuration as well as the end of the
simulation response of the six-ply arrangement subjected to the
7.62-mm round with an initial velocity of 875 m/s are shown in
FIGS. 10a and 10b, respectively. In addition, the residual K.E. and
select velocities collected along the axis of symmetry of the
penetrating bullet are shown in FIGS. 10c and 10d, respectively.
The validation of the V.sub.50 ballistic requirement is herewith
verified since only a relatively small portion of the original K.E.
is carried by the exiting slug.
The Three, 6-mm LGU Subjected to the 7.62-mm Impacting Projectile
with an Initial Velocity of 790 m/s.
[0067] Similarly, the original configuration as well as the end of
the simulation response for the 7-62-mm round impacting the
three-ply arrangement are shown in FIGS. 11a and 11b, respectively.
In addition, the residual K.E. and select velocities collected
along the axis of symmetry of the penetrating bullet are shown in
FIGS. 11(c) and (d), respectively. The validation of the V.sub.50
ballistic requirement is herewith verified since only the backing
material of the section is not fully compromised.
Task 3: Calibration of the Numerical Models
[0068] No calibration was deemed necessary. All numerical models
predict the behavior of each of the experimental results within
satisfactory limits.
Task 4: FE Techniques to Simulate New TIRS Sections Using a a
Combination of ALON, Sapphire (Al.sub.2O.sub.3), IonP/PVB, and the
AAL
[0069] Five examples are addressed to show the benefit of using
ALON, sapphire, IonP, AAL, and polycarbonate layers to achieve what
the typical state-of-the-art bulletproof windows can not.
Example 1
[0070] A 7.62 mm API round with an initial velocity of 793 m/s
(2,600 fps), mass of 10.6 g (164 grains), impacts a composite TIRS
material with alternate layers of ALON and sapphire that are
connected with IonP interlayers. Five such layers (three ALON and
two sapphire) are present with one of the ALON layers being exposed
to impact. An additional sixth layer is made of polycarbonate and
it is on the leeward (away from the impact) side of the section.
The latter is fused to the third from the impacting side ALON layer
with a PVB interface layer. The individual ALON, sapphire, and
polycarbonate layers are each 3.0 mm thick. Each of the IonP and
PVB layers is 1.5 mm thick. FIG. 12 shows a close up of the
numerical setup. The black dots along the vertical axis of
rotational symmetry of the bullet represent stations.sup.1 where
information is extracted concerning the final position of the slug
formation. .sup.1 The spacing of the plotted stations is 2 mm and
they are all located on the axis of symmetry. The first station is
on the tip of the projectile, the second is 2 mm, the third is 4
mm, and the forth is 6 mm away from the impacting tip.
[0071] The overall thickness of the section is 27 mm, for this
particular case. The degree of confidence that the ammunition will
not penetrate the TIRS arrangement is 96%. FIG. 13 shows the
relative compaction of the impacting 7.62 mm entity. The position
versus time variations of select points.sup.1 along the vertical
axis of the bullet suggest that the slug formed penetrates 23 mm
through the thickness of the TIRS (FIG. 13). It causes the bulging
of the section on the side opposite from the impacting surface. The
zero residual K.E. of the slug suggests that the latter is totally
arrested. FIG. 14 shows the final position and formation of the
slug for this particular case.
[0072] In the event that the overall thickness of the TIRS section
is reduced to 23 mm consisting of 2.5-mm individual ALON, sapphire,
and polycarbonate layers whilst the IonP/PVB interface layer
thicknesses remain the same as before, the confidence level drops
to 40%. The type of the 7.62-mm ammunition including its initial
velocity, weight, angle of incidence, in-flight spin, specific
makeup of the material characteristics of the bullet, affect the
confidence level in defeating this level of ballistic threat. At
the other extreme, if the individual layers are increased to 4.2 mm
and the overall thickness of the section is 33 mm then the
confidence level increases to 100%. FIGS. 15a-15b show a similar
section slice for each of these cases as the one described for the
96% level of confidence.
Example 2
[0073] This example addresses the .50 caliber, Ball, Armor
Piercing, M2 round with an initial velocity of 793 m/s (2,600 fps),
weight 52 g (800 grains), impacts a composite TIRS material. The
section is made, starting from the impact side and proceeding in
the through-the-thickness direction, with five alternating layers
of ALON (three in total) and sapphire (two in total) that are
connected with IonP interlayers. The topmost layer is made of ALON.
It is the first layer to be impacted by the round. A 0.75-mm PVB
interlayer connects the third ALON layer to a 3-mm AAL which in
turn is connected through a 0.75-mm IonP layer to three, in total,
alternating ALON (2) and sapphire (1) layers. The latter are
interconnected with PVB interlayers. The last ALON (most distant
from the impacting side) is connected to a polycarbonate layer
using an IonP interlayer. Each ALON and sapphire layer is 3.0 mm
thick while each IonP, PVB, AAL, and polycarbonate layer is 1.5 mm
thick.
[0074] FIG. 16 shows the numerical setup for Example 2. The black
dots along the vertical axis of rotational symmetry of the bullet
represent stations.sup.1 where information is extracted concerning
the final configuration of the slug formation. Additional Lagrange
stations (black dots) are distributed along the thickness of the
section at select locations in order to trace the velocity profile
directly under the impact location.
[0075] The overall thickness of the section is 40.5 mm. The
confidence is 93% that the ammunition will not penetrate the TIRS
arrangement. FIGS. 17a and 17b show the relative compaction of the
impacting .50 caliber bullet penetration (right) and the final rest
position of the slug formed within the section (left).
[0076] The position versus time variation of select points along
the vertical axis of the bullet suggest that the slug formed
penetrates 36 mm through-the-thickness of the TIRS. It causes the
bulging of the section on the opposite side from the impacting
surface with the possibility of forming limited debris.
Example 3
[0077] This example addresses a similar ballistic threat as that of
Example 2, namely the .50 caliber, Ball, Armor Piercing, M2 round
with an initial velocity of 793 m/s (2600 fps), impacting a
modified composite TIRS material. The section is comprised,
starting from the impact side and proceeding in the
through-the-thickness direction, of five alternating layers of ALON
(three in total) and sapphire (two in total) that are connected
with IonP interlayers. The topmost layer is made of ALON and it is
the first layer to be impacted by the round. A 3.0-mm thick PVB
interlayer connects the third ALON layer to three, in total,
alternating ALON (two) and sapphire (one) layers which in turn are
interconnected with PVB interlayers. The last ALON (closest to the
leeward side) is connected to a polycarbonate layer using an IonP
interlayer. The individual ALON and sapphire layers are each 3.0 mm
thick and the polycarbonate layer is 4.5 mm thick. Each IonP layer
is 1.5 mm thick, unless state otherwise. The overall thickness of
the section is 42.0 mm. FIG. 18a shows the makeup of the
section.
[0078] Two numerically induced variations were investigated to
establish the performance of the modified TIRS section with respect
to the .50 caliber, Armor Piercing, M2 round.
Variation 1
[0079] The 46-g (709.5-grains) .50 caliber ammunition is used. The
results are shown in FIGS. 18a-18d. FIG. 18b shows the final (rest)
configuration of the slug formed during the event. The position of
the slug does not vary beyond the 240 ms time-mark as shown in
FIGS. 18c and 18d by the vertical position and velocity outputs,
respectively, of the stations along the axis of symmetry of the
projectile. The final depth of rest is 2.68 cm into the TIRS
section. The confidence is 98% that the ammunition will not
penetrate the TIRS arrangement.
Variation 2
[0080] The 52-g (800-grain) .50 caliber ammunition is used. The
results are shown in FIGS. 19a-19d. FIG. 19a shows the final (rest)
configuration of the slug formed during the event. The position of
the slug does not vary beyond the 260 ms time-mark as shown in
FIGS. 19b and 19d by the vertical position and velocity outputs,
respectively, of the stations along the axis of symmetry of the
projectile. The K.E. of the impacting bullet dissipates within the
first 200 ms and its velocity within the first 260 ms of impact.
The final depth of penetration of the tip of the slug is at 4.05 cm
which is very close to the 4.2 cm total thickness of the composite
section. The center of gravity of the slug formed, however, is at
3.0 cm or less than 72% of the total thickness of the TIRS. As
shown by FIG. 19a spall occurs during this event. The spall
velocity, however, is very low (order of 10-15 m/s) and, thus, the
potential for major injury or death is minimal. The confidence is
85% that the ammunition will not penetrate the TIRS
arrangement.
Example 4
[0081] The results from this example are summarized in Table 1. The
table represents a matrix of results obtained from the simulation
of various levels of ballistic threats as dictated by the UL-752
standard. In particular, Levels I through X are shown herewith. In
all cases, the maximum (upper) value of the velocity range dictated
by the UL-752 ballistic standard is used.
[0082] Table 1 shows the minimum thickness required to defeat each
of these levels of ballistic threat, as well as their respective
areal densities. The velocities, masses, and description of the
individual threats are reported for the sake of completeness. Table
2 shows the through-the-thickness distribution for each of the
layers used in constructing the composite sections. In addition to
the individual layer (ply) thicknesses shown, the uncertainty in
thickness for each of these layers is included.
[0083] The areal densities and thicknesses required by the new
composite section are favorably compared to commercially available
typical laminated glass sections that can defeat the first four
UL-752 Levels. The latter, as reported in the literature (R1), are
31.75, 38.1, 44.5, and 50.8 mm for Levels I through IV,
respectively.
[0084] A visual summary of the UL-752, Level IX, is shown in FIGS.
20a-20d. The initial and final (rest) configurations of the
.30-caliber, 10.8-g ammunition, with an initial impact velocity of
910 m/s are shown in FIGS. 20a and 20b, respectively. The velocity
variation of select points along the ammunition's vertical axis
(axis normal to the impacting surface) is shown in FIG. 20c. It can
be seen that the slug formed is arrested within the first 150 ms
from impact, despite the fact that its K.E. is brought to zero
within 85 ms, as indicated in FIG. 20d. This is due to the fact
that the combination of the "fused" target and bullet is still in
motion beyond 85 ms but within the first 150 ms from impact.
[0085] FIGS. 21a-21d show the equivalent results for the
.50-caliber, 46-g ammunition, with an initial velocity of 942 m/s,
corresponding to the upper bound of the UL-752, Level X ballistic
standard. In this case, the velocity of the slug formed reaches a
stationary state after 275 ms, as shown in FIG. 21c. The slug's
K.E., as seen in FIG. 21d, dissipates before the 235-ms time mark.
This is due to the fact that the combined slug and target body
formed after impact is still in motion between the 235-ms and the
275-ms time marks.
[0086] In all cases, the methodology used in the derivation of the
different materials and section thicknesses employ the use of
numerical methods which explicitly model the individual constituent
thicknesses in conjunction with an optimization module. The latter
takes into consideration a combination of state variables, as well
as the overall section and individual ply thicknesses. It is an
iterative methodology that yields a new cross-section that is
optimized with respect to weight and ply distribution in the
through-the-thickness direction with the aim of defeating each of
the UL-752, Levels I-X ballistic standards.
Example 5
[0087] The importance of an alternate reinforced interlayer section
is addressed in this example. The interface layer consists of a
polymeric material, such as PVB or IonP, and it is reinforced with
single-crystal layers of ALON, a few micrometers thick. The purpose
of the reinforcing crystal found in the interlayer is to produce a
more efficient energy absorption and redirection mechanism. The
reinforcing crystals act as waveguides that divert the energy due
to impact from the through-the-thickness direction to the in-plane
direction. Alternate substitutes to the ALON reinforcement of the
interlayer, are single-crystal layers of aluminum oxide, or
single-crystal layers of any other spinels, or any other single
crystal layers of other high hardness compounds. The optical
quality of the interlayer section is affected by the nature of the
reinforcing crystals.
[0088] A reinforced interlayer with a single crystal acting as a
waveguide to redirect impact energy can be applied to a variety of
laminated materials that include an interlayer and where increased
strength and impact absorption is desirable.
Uses and Investigations
[0089] Some additional capabilities investigated are listed below:
[0090] 1. The composite section can be converted into a section
with variable or reduced light transmissivity. The ballistic
performance of the original section will not be affected. [0091] 2.
The thermal conductivity of the TIRS sections can be enhanced and
yield a reduced U-value suitable for "green" energy applications by
inducing minor modifications to the original composite section. The
ballistic performance of the original section will not be affected.
By substituting one of the plies with a different semi-transparent
material (including spinels or any other photochromic material) the
overall thickness that offers the same level of protection will not
be altered. [0092] 3. The thermal conductivity of the TIRS section
can be enhanced by introducing thermochromic material in one or
more of the interlayers connecting the constituent plies. The
ballistic properties of the section will remain unaffected. The
light transmissivity will be reduced. [0093] 4. The current
composite section can be altered to become a photovoltaic (PV)
section without compromising its ballistic capability. Inclusion of
one or more semitransparent photovoltaic thin-film(s) is necessary.
All the PV types can be integrated within the interfacing layers of
a current TIRS section. It is anticipated that only a single,
thin-film PV will yield equivalent translucent sections as that of
the original TIRS sections. Various degrees of transparency are
possible depending on the application of the composite section. The
ultimate purpose of this portion of the investigation is to provide
ballistic protection and, at the same time, use PV cells to produce
electricity. [0094] 5. A weighted approach of importance for each
of the additional characteristics (ballistic resistance,
transparency, thermal conductivity, thickness, weight, cost of
manufacture and others) is to be incorporated in the analysis and
design of any new TIRS section. [0095] 6. The overall size of the
TIRS can be expanded by incorporating different types of connection
techniques/systems. Some of these include, but are not limited to,
(a) typical glass curtain wall connectors (usually metal
connectors), (b) gasket type of connectors that allow for partial
rotation of the different TIRS units comprising the structure, (c)
continuous joint connections that can be of different degree of
transparency, etc. [0096] 7. Smart glass technologies can be easily
incorporated into the interlayer of the proposed composite,
allowing the control of light and thereby heat transmission.
REFERENCES
[0096] [0097] R1-- "Security Design Guide for Solutia Laminated
Architectural Glazing," Saflex Company, 08810/SOL, 2007.
TABLE-US-00001 [0097] TABLE 1 Characteristics of Composite Sections
Required to Defeat UL-752 Ballistic Levels Ammo UL-752
Characteristics Target Characteristics Confidence Standard
Ammunition Mass Velocity Areal Density Thickness PerCent Level
Description Shots (g) (m/s) (kg/m{circumflex over ( )}2) (mm) (%) I
9 mm 2, 3 8.00 394 17.94 6.95 97 II .357 Magnum 2, 3 10.20 419
19.51 7.51 97 III .44 Magnum 2, 3 15.60 453 29.91 12.10 97 IV .30
Caliber 1 11.70 852 51.98 21.50 98 V 7.62 mm 1 9.70 922 51.96 21.40
98 VI 9 mm 5 8.00 430 20.62 7.52 96 VII 5.56 mm 5 3.56 1033 44.16
17.60 96 VIII 7.62 mm 5 9.70 922 51.96 21.40 95 IX .30 Caliber 1
10.80 910 52.85 21.80 97 X .50 Caliber 1 46.00 942 82.98 35.00 97
VII* 5.56 mm 5 3.56 1310 46.67 18.50 91 *Modified UL 752 Level VII
Standard w/ 30% Velocity
TABLE-US-00002 TABLE 2 Individual Layer and Overall Section
Thicknesses Required to Defeat the UL-752 Ballistic Threats for
Levels I through X Target Thickness UL-752 Ply Standard Ammunition
Thickness Overall Thickness Level Description Material (cm) (cm) I
9 mm ALON 0.300 .+-. .002 0.300 Interlayer 0.150 .+-. .001 0.450
Sapphire 0.245 .+-. .002 0.695 II .357 Magnum ALON 0.300 .+-. .002
0.300 Interlayer 0.150 .+-. .001 0.450 Sapphire 0.301 .+-. .002
0.751 III .44 Magnum ALON 0.300 .+-. .002 0.300 Interlayer 0.150
.+-. .001 0.450 Sapphire 0.300 .+-. .002 0.750 Interlayer 0.150
.+-. .001 0.900 ALON 0.310 .+-. .002 1.210 IV .30 Caliber ALON
0.300 .+-. .002 Interlayer 0.150 .+-. .001 Sapphire 0.300 .+-. .002
Interlayer 0.150 .+-. .001 ALON 0.350 .+-. .002 1.250 Interlayer
0.150 .+-. .001 Sapphire 0.300 .+-. .002 Interlayer 0.150 .+-. .001
ALON 0.300 .+-. .002 2.150 V 7.62 mm ALON 0.300 .+-. .002
Interlayer 0.150 .+-. .001 Sapphire 0.300 .+-. .002 Interlayer
0.150 .+-. .001 ALON 0.350 .+-. .002 1.250 Interlayer 0.150 .+-.
.001 Sapphire 0.300 .+-. .002 Interlayer 0.150 .+-. .001 ALON 0.290
.+-. .002 2.140 VI 9 mm ALON 0.300 .+-. .002 0.300 Interlayer 0.150
.+-. .001 0.450 Sapphire 0.302 .+-. .002 0.752 VII 5.56 mm ALON
0.300 .+-. .002 Interlayer 0.150 .+-. .001 Sapphire 0.300 .+-. .002
Interlayer 0.150 .+-. .001 ALON 0.350 .+-. .002 1.250 Interlayer
0.150 .+-. .001 Sapphire 0.360 .+-. .002 1.760 VIII 7.62 mm ALON
0.300 .+-. .002 Interlayer 0.150 .+-. .001 Sapphire 0.300 .+-. .002
Interlayer 0.150 .+-. .001 ALON 0.350 .+-. .002 1.250 Interlayer
0.150 .+-. .001 Sapphire 0.300 .+-. .002 Interlayer 0.150 .+-. .001
ALON 0.290 .+-. .002 2.140 IX .30 Caliber ALON 0.300 .+-. .002
Interlayer 0.150 .+-. .001 Sapphire 0.300 .+-. .002 Interlayer
0.150 .+-. .001 ALON 0.350 .+-. .002 1.250 Interlayer 0.150 .+-.
.001 Sapphire 0.300 .+-. .002 Interlayer 0.150 .+-. .001 ALON 0.330
.+-. .002 2.180 X .50 Caliber ALON 0.300 .+-. .002 Interlayer 0.150
.+-. .001 Sapphire 0.300 .+-. .002 Interlayer 0.150 .+-. .001 ALON
0.300 .+-. .002 1.200 Interlayer 0.150 .+-. .001 Sapphire 0.300
.+-. .002 Interlayer 0.150 .+-. .001 ALON 0.300 .+-. .002
Interlayer 0.150 .+-. .001 2.250 Sapphire 0.300 .+-. .002
Interlayer 0.150 .+-. .001 ALON 0.300 .+-. .002 Interlayer 0.150
.+-. .001 Sapphire 0.500 .+-. .003 3.500
* * * * *