U.S. patent application number 11/855024 was filed with the patent office on 2008-03-20 for perforated hull for vehicle blast shield.
This patent application is currently assigned to Lockheed Martin Corporation. Invention is credited to Shane F. Mills, Richard S. Stevens.
Application Number | 20080066613 11/855024 |
Document ID | / |
Family ID | 39187203 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080066613 |
Kind Code |
A1 |
Mills; Shane F. ; et
al. |
March 20, 2008 |
PERFORATED HULL FOR VEHICLE BLAST SHIELD
Abstract
A blast energy mitigation structure may employ a V-shaped hull
to decrease the pressure wave imparted to a vehicle during a blast
event, and/or an energy absorbing structure to absorb a portion of
the blast force, thereby minimizing the forces and accelerations
experienced by passengers in the vehicle and consequently reducing
their injuries and increasing their survivability during a blast
event. An exemplary blast energy mitigation structure may have a
V-shaped hull and an energy absorbing structure incorporated into
the chassis of a vehicle such as a Tactical Wheeled Vehicle, the
energy absorbing structure comprising a truss-like structure
including I-beams.
Inventors: |
Mills; Shane F.; (Owego,
NY) ; Stevens; Richard S.; (Endicott, NY) |
Correspondence
Address: |
MILES & STOCKBRIDGE PC
1751 PINNACLE DRIVE
SUITE 500
MCLEAN
VA
22102-3833
US
|
Assignee: |
Lockheed Martin Corporation
Bethesda
MD
|
Family ID: |
39187203 |
Appl. No.: |
11/855024 |
Filed: |
September 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60844655 |
Sep 15, 2006 |
|
|
|
Current U.S.
Class: |
89/36.09 |
Current CPC
Class: |
F41H 7/042 20130101 |
Class at
Publication: |
089/036.09 |
International
Class: |
F41H 5/14 20060101
F41H005/14 |
Claims
1. A perforated blast mitigation hull for attachment to an
underside of a truck for protection of an occupant against an
improvised explosive device detonating from a roadway under the
truck, the perforated blast mitigation hull comprising: a substrate
extending across the truck underside generally in the shape of a
boat hull and including rocker panels in a raked orientation rising
away from a center of the underside of the truck; and perforations
formed in said substrate; wherein the perforations formed in the
substrate are selectively located and adapted to permit the
substrate to hold a blast of a predetermined magnitude emanating
from an improvised explosive device detonating from the roadway
under the truck; and wherein the perforations formed in the
substrate are selectively located and adapted to direct in a
desired direction a blast from an improvised explosive device
detonating from the roadway under the truck.
2. The blast mitigation hull of claim 1, wherein the rocker panels
are planar.
3. The blast mitigation hull of claim 1, wherein the substrate is
formed in a modified "V" shape.
4. A blast mitigation hull for attachment to an underside of a
vehicle for protection of an occupant against an explosive device
detonating under the vehicle, the blast mitigation hull comprising:
a substrate extending across the vehicle underside generally in the
shape of a hull and including portions rising away from a center of
the underside of the vehicle; and perforations formed in the
substrate; wherein the perforations formed in the substrate are
selectively located and adapted to permit the substrate to hold a
blast emanating from an explosive device detonating under the
vehicle; and wherein the perforations formed in the substrate are
selectively located and adapted to direct in a desired direction a
blast from an explosive device detonating under the vehicle.
5. The blast mitigation hull of claim 4, wherein the vehicle is a
truck.
6. The blast mitigation hull of claim 4, wherein the vehicle is a
Tactical Wheeled Vehicle.
7. The blast mitigation hull of claim 4, wherein the portions
comprise rocker panels.
8. The blast mitigation hull of claim 7, wherein the rocker panels
are planar.
9. The blast mitigation hull of claim 4, wherein the substrate is
formed in a modified "V" shape.
10. A method of protecting an occupant of a vehicle against an
explosive device detonating under the vehicle, the method
comprising: providing a blast mitigation hull comprising: a
substrate extending across the vehicle underside generally in the
shape of a hull and including portions rising away from a center of
the underside of the vehicle, and perforations formed in the
substrate; and attaching the blast mitigation hull to the underside
of the vehicle; wherein the perforations formed in the substrate
are selectively located and adapted to permit the substrate to hold
a blast emanating from an explosive device detonating under the
vehicle; and wherein the perforations formed in the substrate are
selectively located and adapted to direct in a desired direction a
blast from an explosive device detonating under the vehicle.
11. The method of claim 10, wherein the vehicle is a truck.
12. The method of claim 10, wherein the vehicle is a Tactical
Wheeled Vehicle.
13. The method of claim 10, wherein the portions comprise rocker
panels.
14. The method of claim 13, wherein the rocker panels are
planar.
15. The method of claim 10, wherein the substrate is formed in a
modified "V" shape.
Description
[0001] The present invention relates generally to a blast energy
mitigation structure, method of system integration, and method of
fabrication, and more particularly to a vehicular frame
construction which is particularly suited for use in vehicles that
may be subjected to explosive blasts from mines and improvised
explosive devices.
[0002] Tactical wheeled vehicle (TWV) based crew members are often
subjected to blast events from mines and improvised explosive
devices (IEDs). Three of the types of blast events commonly
encountered are (1) mines that are remotely detonated underneath
the body of a vehicle, (2) mines that are contact--or
pressure--detonated underneath a wheel of a vehicle, and (3) IED
road blasts. In either case, a vehicular mine blast typically
subjects a TWV to forces and accelerations that are, in turn,
transferred to the TWV based crewmembers inside the vehicle. Such
forces and accelerations are capable of causing extensive damage to
a human body, and can thereby result in the death of TWV based crew
members. This poses a problem as to how to increase the
survivability of TWV based crew members during a mine or IED blast
event.
[0003] The blast mitigation structure of the present invention may
divert and/or absorb the blast energy sufficiently to attenuate the
forces and accelerations exerted on the human body, thereby
decreasing crew members' actual bodily injury to a survivable
level.
[0004] In an exemplary embodiment of the present invention, the
problem is addressed by a combination of a "V-hull" shape and an
energy absorbing structure. The V-hull shape, or V-hull, allows
gaseous venting, thereby decreasing the pressure wave imparted to a
vehicle during a blast event and decreasing subsequent negative
effects of mine or IED blasts under a vehicle. The energy absorbing
structure is designed to collapse under certain blast forces, based
on its physical geometry and material properties. The energy
absorbing structure may also serve as a skeleton that forms the
shape of the V-hull. The combination of these two features may
reduce the forces and accelerations experienced by crew members,
and may thereby reduce their injuries and increase their
survivability during a blast event.
[0005] The present invention may be tunable to address various mine
or IED threats, within the same vehicle platform. The present
invention may also be configured for use with different platforms
that lend themselves to space and weight ranges similar to that of
a TWV. The present invention may be adapted, for instance, for use
with vehicles designed to transport dignitaries or other officials,
commercial armored cars and vehicles, or helicopter and ground
attack aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The accompanying drawings are incorporated in and constitute
a part of the specification.
[0007] FIG. 1 shows an embodiment of the blast mitigation structure
with a V-hull shape and an energy absorbing structure combined.
[0008] FIG. 2 shows an embodiment of the blast mitigation structure
with a V-hull shape and an energy absorbing structure both
incorporated into a chassis of a vehicle.
[0009] FIG. 3 shows an embodiment of an energy absorbing structure
with a standoff distance and collapsible cross-bracing incorporated
into the energy absorbing structure.
[0010] FIG. 4 shows an embodiment of the present invention where
cutout sizes and placement within the webs of structural members
are incorporated into the energy absorbing structure's
geometry.
[0011] FIG. 5 shows an embodiment of an energy absorbing structure,
with both a standoff distance and collapsible cross-bracing,
incorporated into a chassis of a vehicle.
[0012] FIG. 6 shows an embodiment of the blast mitigation structure
with a V-hull shape and an energy absorbing structure both
incorporated into a chassis of a vehicle, and further illustrates a
standoff distance and a collapsible seat base.
[0013] FIG. 7 shows an embodiment of the present invention with
both a perforated substrate and a polyurea coating incorporated
into a V-hull of a blast mitigation structure.
DETAILED DESCRIPTION
[0014] While the exemplary embodiments illustrated herein may show
the various features of the present invention, it will be
understood that the features disclosed herein may be combined
variously to achieve the objectives of the present invention.
[0015] Turning to FIG. 1, an embodiment of the blast energy
mitigation structure [100] is shown where a V-hull shape [101] and
an energy absorbing structure [102] are combined. An embodiment of
the V-hull shape [101] has three planes, one inner and two outer,
that run longitudinally along the underside of the energy absorbing
structure [102] and are joined along two longitudinal vertices
formed by supporting structural members [111, 112]. The inner plane
[103] is oriented substantially parallel to the planed formed by
the supporting structural members [111, 112] and runs along the
longitudinal axis of the energy absorbing structure. The outer
planes [104, 105] are joined with the inner plane along two
longitudinal vertices. Each outer plane extends outward and upward
from the inner plane, thereby forming a cross-section that
resembles a modified "V" in form, similar, for example, to a boat
hull. In the event of a blast from a mine or IED, the "V" form of
the V-hull shape allows for gaseous venting, thereby diverting and
decreasing the pressure wave imparted to the blast energy
mitigation structure during the blast event.
[0016] The energy absorbing structure [102] shown in FIG. 1 is made
of structural members that are assembled to form a truss-like
structure that may collapse under certain blast forces. The energy
absorbing structure may also form the shape of and support the
V-hull shape.
[0017] The V-hull may be backed up by a truss and gusset structure
having cutouts and formed in a unitary cross-brace. Such a
structure may absorb blast forces and add strength to a vehicle
chassis. In one embodiment, a blast energy mitigation structure may
comprise an energy absorbing structure attached to the underside of
a vehicle chassis, adding rigidity thereto, and a hull connected to
and running longitudinally along the underside of the energy
absorbing structure, the energy absorbing structure comprising
structural members fastened together to form a truss-like
structure, and the truss-like structure comprising an upper and a
lower flange portion connected by a web portion. The blast energy
mitigation structure may further comprise a series of vertical
structural members effective to space the truss-like structure from
the vehicle chassis by a standoff distance. The truss-like
structure may be a unitary structure vertically spaced from the
underside of the vehicle chassis and shaped in a horizontal "X"
pattern extending across the underside of the vehicle chassis.
[0018] FIG. 2 shows an embodiment of the invention with the V-hull
shape [201] and the energy absorbing structure [202] incorporated
into the chassis of a vehicle. In this embodiment, the longitudinal
axes of the V-hull shape and the energy absorbing structure are
substantially parallel to the longitudinal axis of the vehicle. One
aspect of the energy absorbing structure shown is a standoff
distance [206] between the upper and lower portions of the energy
absorbing structure. This spatial gap is one aspect of the energy
absorbing structure's geometry that enables the structure to
collapse under certain blast forces, thereby reducing the forces
and accelerations ultimately transferred from the exterior of a
vehicle to the crew members inside the vehicle.
[0019] Turning to FIG. 3, an exemplary embodiment of the energy
absorbing structure [302] is shown with a standoff distance [306]
and collapsible cross-bracing [307] incorporated into the design of
the energy absorbing structure. In this embodiment, the
cross-bracing consists of structural members connected in a
truss-like framework with portions of the web elements [308]
removed. The resulting "cutouts" [309] in the web reduce the
flexural strength of a structural member, for a given material.
Specific web cutout size and placement within the webs of
structural members may be designed into the energy absorbing
structure's geometry such that the structure will collapse under
certain blast forces.
[0020] FIG. 4 shows an embodiment of the present invention where
the cutout size and placement within the webs of structural members
are incorporated into the energy absorbing structure's geometry
such that the structure may collapse, based on correspondingly
increasing levels of blast energy. The figure shows an "X" pattern
truss-like framework [407] comprised of structural members. Views
A-A and B-B show side and end views, respectively, of a structural
member having cutouts [409] that decrease in size as one moves
toward the upper end of the structural member. As one moves toward
the upper end of the structural member, the thickness of the web
[408] increases as well. These features, individually and
collectively, may serve to increase the strength of the web as one
moves toward the upper end of the structural member, and thereby
adapt the structure for collapsing successively, based on
correspondingly increasing levels of blast energy. As shown in
alternate View A-A, the web cutout may take various shapes and
sizes.
[0021] FIG. 5 shows an embodiment of the present invention where
the energy absorbing structure [502] is incorporated into the
chassis of a vehicle. The left and right ends of the figure
represent the forward and aft portions, respectively, of a vehicle
cab firewall and rear wall as well as the midsection of the vehicle
chassis where the cab is typically integrated, although the front
and rear sections of the chassis may also serve as mounting
locations. This embodiment of the energy absorbing structure
combines web cutouts [509] within the web [508] of the
cross-bracing [507] structural members, as well as a standoff
distance [506] between the upper and lower portions of the energy
absorbing structure. These aspects of the energy absorbing
structure's geometry, along with structural material selection,
enable the structure to be designed to collapse under certain blast
forces, thereby reducing the forces and accelerations ultimately
transferred from the exterior of a vehicle to the crew members
inside the vehicle. As an example, the structural geometry of this
embodiment may be used to form a collapsible seat base upon which a
crew member's seat may be installed in the vehicle, thereby
providing a structural blast mitigation path for the seated crew
member.
[0022] FIG. 6 shows an embodiment of the present invention where
both the V-hull shape [601] and the energy absorbing structure
[602] have been incorporated into a TWV or similar type vehicle. In
this embodiment, the longitudinal axes of the V-hull shape and the
energy absorbing structure are substantially parallel to the
longitudinal axis of the vehicle. This figure illustrates how the
energy absorbing structure [602] may be used to both form the shape
of and support the V-hull [601]. It further illustrates a standoff
distance [606] feature of the energy absorbing structure, as well
as how the structure may be used to form a collapsible seat base
upon which a crew member's seat [610] may be installed in the
vehicle.
[0023] In a V-hull geometry for blast mitigation, the V-hull
geometry may dissipate blast force, create packaging space for
componentry, and increase mobility by raking the rocker panels. The
V-Hull may be backed up by a blast absorption structure such as
honeycombed steel or trusses. In one embodiment, a blast energy
mitigation structure adapted to surround and cover an energy
absorbing structure may comprise a V-hull connected to and running
longitudinally along the underside of the energy absorbing
structure, comprising three planar surfaces, one inner and two
outer, that run longitudinally along the underside of the energy
absorbing structure and are joined along two longitudinal vertices
formed by supporting structural members of the energy absorbing
structure, the inner planar surface being substantially parallel to
the supporting structural members, and each outer planar surface
depending outward and upward from the inner planar surface, thereby
forming a cross-section that resembles a modified "V" in form. The
blast energy mitigation structure may be adapted for attachment to
a tactical wheeled vehicle, air vehicle, or tracked vehicle, for
example.
[0024] An exemplary embodiment of the present invention may include
a tunable feature, whereby the blast energy mitigation structure
may be designed or "tuned" to accommodate an expected level of
blast energy. For instance, blast levels are often rated by the
Unites States Military on a scale of one to three, with three
representing the highest level of blast energy. A certain blast
level may be anticipated in a given location or scenario, based on
reconnaissance or other intelligence. Accordingly, the blast energy
mitigation structure could be tuned, or structurally designed, to
accommodate the expected blast level and subsequently incorporated
into vehicles to be used in that location or scenario, thereby
providing sufficient blast energy mitigation with accompanying
design efficiency. Additionally, the blast energy mitigation
structure may be adapted to different sections of a vehicle, such
as the cargo or troop carrier sections of a TWV.
[0025] The blast mitigation structure may be adapted to bolt in and
bolt out of different vehicles in the field. This may allow for
selecting and installing a Blast Mitigation System that is rated
for a particular blast level (i.e., level 1, 2, or 3). Such a
system may be installed, removed, and replaced in the field and
could be used as an alternative to, or in conjunction with, a
"crumple zone" concept. In one embodiment, a line replaceable blast
energy mitigation structure for attachment to a vehicle underside
may comprise an energy absorbing structure and a hull connected to
and running longitudinally along the underside of the energy
absorbing structure, such that the line replaceable blast energy
mitigation structure may be adapted for attachment to and removal
from a tactical wheeled vehicle in the field in a combat area. In
another embodiment, a blast mitigation system may comprise a first
line replaceable blast energy mitigation structure for attachment
to a vehicle underside comprising an energy absorbing structure and
a hull connected to and running longitudinally along the underside
of the energy absorbing structure, such that the first line
replaceable blast energy mitigation structure may be adapted to
absorb a first particular blast level derived from a plurality of
military standard blast levels, and a second line replaceable blast
energy mitigation structure for attachment to a vehicle underside
comprising an energy absorbing structure and a hull connected to
and running longitudinally along the underside of the energy
absorbing structure, such that the second line replaceable blast
energy mitigation structure may be adapted to absorb a second
particular blast level, derived from a plurality of military
standard blast levels, that is different than the first particular
blast level.
[0026] Alternatively, an embodiment of the present invention may
include variable energy absorption capability within a single blast
energy mitigation structure. This may be accomplished via a series
of structural zones within the blast energy mitigation structure.
These structural zones could be designed with structural geometries
and/or materials that vary from one zone to another such that the
zones would collapse in succession, based on correspondingly
increasing levels of blast energy. As an example, a vehicle
equipped with a blast energy mitigation structure of this
embodiment of the present invention, encountering a level-one mine
or IED blast could experience collapsing of zone 1 of the blast
energy mitigation structure. A similarly equipped vehicle,
encountering a level-three mine or IED blast could experience
collapsing of zones 1, 2, and 3 of the blast energy mitigation
structure. This configuration could provide the greatest benefit to
a vehicle crew from an operational scenario and mission tempo
standpoint. The crew could be protected at all times to the highest
level possible, without spending time on vehicle modifications.
[0027] A blast mitigation structure may be adapted to allow
different zones of the structure to collapse progressively as the
vehicle experiences increasing magnitudes of blast force
corresponding to military standard blast forces. This may be
implemented by increasing the structural web strength toward the
vehicle. Decreasing the web cutout size and/or increasing the web
thickness may achieve the increase in web strength. In an
embodiment, a blast energy mitigation structure adapted to surround
and cover an energy absorbing structure may comprise a hull
connected to and running longitudinally along the underside of the
energy absorbing structure, comprising two or more planar surfaces
that run longitudinally along the underside of the energy absorbing
structure and are joined along one or more longitudinal vertices
formed by supporting structural members of the energy absorbing
structure, the energy absorbing structure being comprised of
structural members fastened together to form a truss-like
structure, the truss-like structure forming the shape of and
supporting the hull, and the energy absorbing structure further
comprising a series of structural zones, each zone in the series
being adapted to collapse sequentially under progressively greater
structural loads. In another embodiment, each zone of the blast
energy mitigation structure may be adapted to mitigate a different
level of blast force. The different levels of blast force may
correspond to militarily derived standard levels. In another
embodiment, the blast energy mitigation structure may have three
structural zones, corresponding to three militarily derived
standard levels of blast force. A method of mitigating vehicular
based blast energy might include specifying a specific level of
expected blast energy from a blast event, designing a blast energy
mitigation structure to absorb blast energy from the blast event by
adapting the physical geometry of the structure to absorb the
specific level of expected blast energy--by including, for
instance, a series of zones that collapse sequentially under
progressively greater levels of blast energy--and incorporating the
blast energy mitigation structure into a vehicle for use in
geographic areas subject to blast events.
[0028] Yet another embodiment of the present invention may include
the use of a coating that could be applied to structural members of
the blast energy mitigation structure to provide a containment
surface or "skin." When subjected to a mine or IED blast, the skin
could act to contain the blast force and may distribute the force
to selected blast energy mitigation structural members. In an
additional embodiment of the present invention, the skin could be
selectively perforated in order to partially exhaust gases
associated with a mine or IED blast and to effectively guide the
blast force, for example, in desired directions.
[0029] Perforations added to the hull of a blast mitigation
structure may result in baffling and dampening effects that may
serve to "hold" the blast longer before hull rupture occurs.
Additionally, a polyurea coating could be applied to the hull to
increase the tensile strength of the hull substrate without adding
significant weight, so that the outer hull "skin" may "hold" the
blast longer. In one embodiment, a blast mitigation hull for
attachment to a vehicle underside may comprise a perforated
substrate extending across the vehicle underside and a coating
applied to the substrate in an amount effective to increase the
tensile strength of the hull in an explosive blast. In another
embodiment, a blast mitigation hull for attachment to a vehicle
underside may comprise a perforated substrate extending across the
vehicle underside, the substrate comprising perforations
selectively located and adapted to direct a blast in a desired
direction. In yet another embodiment, a blast mitigation hull for
attachment to a vehicle underside may comprise a substrate
extending across the vehicle underside, the substrate comprising a
polyurea coating applied in an amount effective to increase the
tensile strength of the hull in an explosive blast.
[0030] FIG. 7 shows an embodiment of the present invention with
both a perforated substrate [713] and a polyurea coating [714]
incorporated into a V-hull [701] of a blast mitigation
structure.
[0031] In another embodiment of the present invention, equipment
may be housed in the areas or cavities created by various blast
mitigation structures. Such equipment could be designed to take on
characteristics similar to those of the aforementioned structures.
As an example, air tanks, for use with a Central Tire Inflation
System (CTIS) and/or a vehicle suspension system, could be
installed in cavities within a blast mitigation structure. When
subjected to blast forces, a pressure vessel, such as an air tank,
may collapse and release its pressurized contents in a predictable
manner, so as to not behave like a projectile.
[0032] Compressed air tanks could be placed within the hull brace
of a blast mitigation structure to absorb blast energy. Such
devices may be deformed and possibly destroyed as a result of
absorbing energy. These devices may also have dual use as on-board
sources of compressed air. In one embodiment, a blast energy
mitigation structure may comprise an energy absorbing structure
attached to the underside of a vehicle chassis and adding rigidity
thereto, a hull connected to and running along the underside of the
energy absorbing structure, the hull defining a three-dimensional
space under the vehicle chassis, and a compressed air tank placed
within the three-dimensional space under the vehicle chassis. In
another embodiment, the compressed air tank may serve as a source
of compressed air for a central tire inflation system on the
vehicle. In another embodiment, the compressed air tank could be
elongated in a direction parallel to an underside of the vehicle
chassis. In yet another embodiment, a blast energy mitigation
device may comprise a cylindrical, air-tight vessel, having along
its length a center portion and two end portions, one on either
side of the center portion, two or more straps, circumferentially
attached to the vessel near each of the end portions, and one or
more valves attached to the vessel. A method of mitigating
vehicular based blast energy may comprise specifying an expected
level of blast energy from a blast event, designing a blast energy
mitigation structure to absorb blast energy from the blast event by
adapting the physical geometry of the structure to absorb the
specific level of expected blast energy, and incorporating the
blast energy mitigation structure into a vehicle for use in
geographic areas subject to blast events, to include a cylindrical,
airtight vessel installed horizontally within the blast energy
mitigation structure, thereby providing an energy absorption
device.
[0033] Any of the above features could be combined into an
embodiment of a vehicular based mine blast energy mitigation
structure.
[0034] It is, therefore, apparent that there is provided in
accordance with the present invention, a structure for mitigating
the blast energy resulting from a mine or IED blast. While this
invention has been described in conjunction with a number of
embodiments, it is evident that many alternatives, modifications
and variations would be or are apparent to those of ordinary skill
in the applicable arts. Accordingly, applicants intend to embrace
all such alternatives, modifications, equivalents and variations
that are within the spirit and scope of this invention.
* * * * *