Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ARMOUR ARRANGEMENT
FIELD OF THE INVENTION
The invention relates to an armour arrangement, and more particularly, but
not exclusively, to an armour arrangement suitable for use with armoured
vehicles to protect a surface of the vehicle from shaped charges.
BACKGROUND TO THE INVENTION
A shaped charge is an explosive charge shaped to focus the effect of the
explosive's energy. Various types of shaped charges are used to cut and form
metal, initiate nuclear weapons, and penetrate armour. A typical device
consists of a solid cylinder of explosive with a metal-lined conicaf hollow in
one end and a central detonator, array of detonators, or detonation wave
guide at the other end. The enormous pressure generated by the detonation
of the explosive drives the liner contained within the hollow cavity inward to
collapse upon its central axis. The resulting collision forms and projects a
high-velocity jet of metal forward along the axis. Most of the jet material
originates from the innermost layer of the liner, about 10% to 20% of its
thickness. The remaining liner material forms a slower-moving slug of
material.
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A typical modern lined shaped charge can penetrate armour steel to a depth
of 7 or more times the diameter of the charge's cone.
A shaped charge is also know as an Explosively Formed Penetrator or
Explosively Formed Projectile (or "EFP" for short), Explosively-Forged
Projectile, Explosively-Forged Penetrator, Self-Forging Warhead (SFW), and
Self-Forging Fragment (SFF).
Shaped-charges and explosively formed projectiles are of major concern in
modern day warfare, since they are relatively easy to produce and highly
effective in penetrating armour plating of a light armour vehicle.
Composite armour, where sheets of different materials are located and
secured atop one another, have been used with limited success heretofore,
but do not prove to be sufficiently effective against the new threats of
shaped
charges and EFP's.
An example of known composite armour is laminate glass armour, which
comprises silica/polycarbonate plastic layers sandwiched between glass
layers. Disadvantages of laminate glass armour are that it is relatively very
expensive to produce and relatively very heavy, since a sheet of laminate
glass is approximately 3 inches thick and weights approximately 30 LbIFt2.
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OBJECT OF THE INVENTION
It is accordingly an object of the invention to provide an armour arrangement
that will, at least partially, alleviate the disadvantages of existing
solutions.
It is a further object of the invention to provide an armour arrangement that
will be a useful alternative to existing armour arrangements.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided an armour
arrangement for covering a surface to be protected, comprising a plurality of
disruption members being located adjacent one another and being at least
partially spaced apart from one another, wherein the disruption members are
angularly displaced relative to the surface to be protected.
The disruption members may be arranged substantially parallel relative to one
another.
Each disruption member may have a first impact side, being the side distal
from the protected surface, and a second exit side, being the side proximate
the protected surface, the arrangement being such that the armour
arrangement includes a first impact face, being the face formed by the impact
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sides of the disruption members, and a second exit face, being the face
formed by the exit sides of the disruption members.
The exit side of one disruption member may at the least partially overlap an
adjacently positioned disruption member.
The disruption members may be planar.
Alternatively, the disruption members may be arcuate.
The disruption members may be of a non-linear configuration, wherein an
angle between the impact side of the member and the protected surface is
different to an angle between the exit side of the member and the protected
surface.
Each disruption member may be formed from a single sheet of material.
Alternatively, each disruption member may include a plurality of disruption
bodies.
Each disruption body may be planar.
Alternatively, each disruption body may be arcuate.
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The disruption bodies may be positioned adjacent one another in a side-by-
side arrangement and in an angularly offset configuration, to form the
disruption member.
The disruption bodies may be arranged relative to one another, such that the
disruption member is in the shape of a half-parabola.
The disruption bodies may be connected to one another to form the disruption
member by a retaining frame, which may define a plurality of openings for
receiving opposite outer ends of the bodies.
Alternatively, the disruption bodies may be connected to one another by being
bonded to one another.
The armour arrangement may be positioned in front of the surface to be
protected by being attached thereto by attachment means.
The surface may be an external surface of a hull section of an armoured
vehicle.
According to a second aspect of the invention, there is provided an armoured
vehicle including the armour arrangement according to the first aspect of the
invention.
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The armour arrangement may be attached to the armoured vehicle in order to
protect the outer surface of the vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described further by way of a non-limiting example
with reference to the accompanying drawings wherein:
figure 1 is a perspective view of an armour arrangement according to a
preferred embodiment of the invention, being partially
assembled;
figure 2 is a perspective view of the armour arrangement of figure 1,
being assembled;
figure 3 is a cross sectional side view of the armour arrangement of
figures 1 and 2; and
figure 4 is a schematic illustration of the armour arrangement of figures 1
to 3, used in examples 1 and 2.
DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Referring to the drawings, an armour arrangement according to a preferred
embodiment of the invention is generally designated by reference numeral 10.
The armour arrangement 10 is used to cover a surface (not shown) to be
protected, such as an outer surface of a hull of an armoured vehicle (all not
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shown). The armour arrangement 10 is positioned in front of and is secured to
the surface, by attachment means (also not shown).
The armour arrangement 10 comprises a plurality of disruption members 12
located adjacent one another, being at least partially spaced apart from one
another and being angularly displaced relative to the surface.
Each disruption member 12 has a first impact side 14 and a second exit side
16. The first impact side 14 is the side distal from the protected surface and
the second exit side 16 is the side proximate the protected surface. The
arrangement is therefore such that the armour arrangement 10 has a first
impact face 18, which is formed by the first impact sides 14 of the disruption
members 12, and a second exit face 20, which is formed by the second exit
sides 16 of the disruption members 12.
The disruption members 12 are arranged substantially parallel relative to one
another with the exit side 16 of one disruption member 12 at the least
partially
overlapping the disruption member 12 positioned adjacent it. The disruption
members 12 are of a non-linear configuration, wherein an angle between the
impact side 14 of the member 12 and the protected surface is different to an
angle between the exit side 16 of the member 12 and the protected surface.
Each disruption member 12 is arcuate in cross-section and includes three
disruption bodies (jointEy referred to as 22), a first body 22.1, a second
body
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22.2 and a third body 22.3. The disruption bodies 22 are planar and
positioned side-by-side to form the arcuate disruption member 12. The bodies
22 are further arranged in an angularly offset configuration, such that each
disruption member 12 is in the shape of a half-parabolic curve. Specifically,
the angle of the first body 22.1, relative to the horizontal, is approximately
60 ,
the angle of the second body 22.2, relative to the horizontal, is
approximately
45 , and the angle of the third body 22.3, relative to the horizontal, is
approximately 30 .
The disruption bodies 22 are all made of 5 mm thick armour plate steel, with a
Brinell hardness of between 500 and 600, such as Amiox500TM . The first body
22.1 is 30 mm wide and the second and third bodies 22.2 and 22.3 are both
25 mm wide each.
The disruption bodies 22 are connected to one another to form the disruption
member 12 by a retaining frame 24, as shown in figures 1 and 2. The
retaining frame 24 defines a plurality of openings 26 for receiving opposite
outer ends of the bodies 22. However, the disruption bodies 22 could also be
bonded to one another by, for example, having their adjacent ends welded
together.
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Below, as two examples, are the set up and resufts of triais that have been
conducted to test the functionality of the armour arrangement 10, as
described above.
Example '!
Referring to figure 4, the armour arrangement 10 in this example comprises
three disruption bodies 22.1, 22.1 and 22.3, each being 5 mm thick and made
from RAMOR500" armour plate, having a Brinell hardness of 500. The first
body 22.1 is 42.5 mm wide, the second body 22.2 is 23.5 mm wide and the third
body 22.3 is 17mm wide. The angle of the first body 22.1, relative to the
horizontal, is 63 , the angle of the second body 22.2, relative to the
horizontal, is
46 , and the angle of the third body 22.3, relative to the horizontal, is 18 .
The armour arrangement 10 was positioned in front of the hull section of an
armoured vehicle, with the exit face 20 of the armour arrangement 10 facing
the
surface of the hull and being approximately 435 mm from the surface.
An EFP was fired at the armour arrangement 10 from 2 m perpendicularly in
front of the armour arrangement 10.
It was found that the combination of the armour arrangement 10 and the hull of
the armoured vehicle warded off the EFP. There were only minor splatter
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markings on the outer surface of the hull. The EFP thus had no effect on the
inside of the hull.
Example 2
Using the same armour arrangement 10 described in example I above, the
armour arrangement 10 was positioned approximately 321 mm from the surface
of the hull. The EFP was again fired 2 m from the armour arrangement 10. In
this trial, the outer surface of the hull was relatively more damaged, but the
EFP
still did not penetrate the hull.
It has been shown that the damage sustained by armour plates during physical
shaped-charge impact is based on the capability of the shaped charge to melt
the material, which it is impacting. Further confirmation of this observation
is the
presence of splatter-pattems, consistent with molten metal droplets. It can
therefore be concluded that a shaped-charge (or EFP) is most accurately
modelled or approximated by the assumption that it is a phenomenon with:
i) High-speed (momentum/kinetic energy)
ii) High temperature (thermal energy)
iii) High pressure
iv) High viscosity (molten metal)
v) A spearhead-shape
vi) A molten/fluid metal slug or "jet" consistency
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It is therefore submitted that in order to avoid death or serious injury due
to a
blast, one either needs to avoid the blast or the blast should be absorbed or
deflected.
In the same vein, it is submitted that one can generalise and apply this
philosophy to shaped charges too. Unfortunately, avoidance is quite
improbable, thus the only two remaining options are absorption (dissipation
through momentum redistribution) or deflection (redirection of the jet to
avoid
impact.
The basic concept of the present invention is to (i) deflect the molten metal
jet as
much as possible or, partially failing that, to (ii) dissipate the
concentrated linear
momentum of the single slug or jet by spreading it over a larger area
(henceforth
called splattering or scattering) by forcing it to break into smaller parts
and
changing its direction of motion through collision phenomena.
The former objective (deflection) would ideally be best facilitated by having
a
deflector-channel-shaped arrangement of plates which present a surface with a
very high NATO (North Atlantic Treaty Organisation) impact angle at the point
of
first impact, gradually transitioning to one having an impact angle parallel
to or
smaller than the surface tangent vector of the main armour behind it.
The latter objective (dissipation or disruption) would ideally be achieved by
placing as many as possible thin (ca. 1 mm thick) plates at a slant to
"disrupt"
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the flow (i.e. redirect, redistribute and convert the linear momentum) as many
times as possible.
It has been found that thicker disruption bodies 22 provide more protection
and
deflection capability per body 22, whilst the thinner bodies 22 provide more
disruptive capability.
It has further been found that the multi-layered slanted body layout of the
armour
arrangement 10 proves to be effective in disrupting and diverting the jet
originating from an EFP. There is a trade-off between structural strength and
mass per unit area (which is attempted to be kept under 100 kg/m2).
It will be appreciated that variations in detail are possible with an armour
arrangement according to the invention without departing from the scope of
the appended claims.
For example, the disruption members could each be formed from a single
sheet of material, instead of a plurality of disruption bodies connected to
one
another. The disruption members could further be planar or arcuate formed by
bending a single plate of material, to form a continuous smooth shape.
Further, the number of disruption bodies making up the disruption member
may vary and the shape of the disruption bodies could be arcuate instead of
planar.
