US20190310055A1

US20190310055A1 - Blast deflector

Info

Publication number: US20190310055A1
Application number: US15/948,349
Authority: US
Inventors: Celyn M. Evans; Reed Pelly; Jason Kremar; Aaron Ward
Original assignee: Pratt and Miller Engineering and Fabrication Inc
Current assignee: Pratt and Miller Engineering and Fabrication Inc
Priority date: 2018-04-09
Filing date: 2018-04-09
Publication date: 2019-10-10

Abstract

A blast energy deflector to reduce load and energy transmitted to a vehicle from buried mines or improvised explosive device (IED) threats. The deflector may add stiffness to the hull thereby protecting or delaying deformation or damage to the vehicle underside. The deflector may be hollow, filled with plastic or other composites to dissipate blast energy, or solid, and may be detachably affixed to the vehicle underside.

Description

STATEMENT OF GOVERNMENT INTEREST

This disclosure was made in part with Government support by The United States Department of the Army. The Government has certain rights in the disclosure.

TECHNICAL FIELD

This disclosure relates to an energy deflector to reduce load and energy transmitted to any vehicle structure such as a body on frame or a monocoque vehicle structure, or any other vehicle structure, from buried mines or improvised explosive device (IED) threats. The deflector may add stiffness to the hull thereby protecting or delaying deformation or damage to the vehicle underside. The deflector may be hollow, filled with plastic or other composites to dissipate blast energy, or solid, and may be detachably affixed to the vehicle underside.

BACKGROUND

Existing combat vehicles are extensively used in conflict theaters where asymmetric warfare occurs. In such a conflict, it is very effective to use simple weapons to destroy very expensive vehicles and other equipment. IEDs and buried mines are especially favored by such asymmetric forces. They are cheap to make, easy to conceal and deliver a large amount of energy into a small area of a very expensive piece of equipment. The hulls of any vehicle subjected to an IED or buried mine are damaged and the personnel are injured, or worse. Part of the issue is that the blast from such a device is concentrated upwardly against a small part of a vehicle, thereby concentrating the destructive effect of the impact. Some vehicles have used reinforced hull designs or have adopted vehicle hull designs calculated to deflect or spread the blast force over a large area. However, there are many lighter armored vehicles where such design parameters are not used, or where a pre-existing vehicle does not incorporate such a design In addition, vehicles previously designed to withstand blast events from previous IEDs and buried mines now face much more powerful IEDs and buried mines, thereby reducing the protective value of previous designs. Moreover, vehicles with segmented armor plating may be especially susceptible to concentrated blast force.
Improvements in blast energy deflection are continuing and needed. In one embodiment, the blast deflector may be a piece of angled welded plate metal attached to the underside of a vehicle. In other vehicles with segmented armor, the deflectors may be attached to a channel with fasteners along the length of the vehicle to impart protection over the entire underside of the vehicle. Attachment of the device to the vehicle is not necessarily rigid. The blast deflector includes mounting the deflector on an energy absorber or spacer to decouple it from the main vehicle hull structure. The device can remain effective at reducing transferred energy from a blast event to the hull even if it eventually or quickly is separated from the structure and the device works by directing energy away from the vehicle early in the blast event. The structure and/or stiffness provided by the device can assist in protecting the structure above it and dispersing the blast energy over a greater area, thereby dissipating it. The device may be flexibly mounted to allow for closer placement to the ground without negatively affecting vehicle mobility.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vehicle having a hull shape;

FIG. 2A is a cross sectional view of a blast deflector according to one embodiment;

FIG. 2B is a perspective view of a blast deflector with concave sides;

FIG. 2C is perspective view of a blast deflector with convex sides;

FIG. 3 is a representation of a detail of the underside of a vehicle hull showing an arrangement of apertures to affix the blast deflector to the vehicle hull;

FIG. 4 is a cross sectional view of a blast deflector according to one embodiment mounted on a vehicle hull;

FIG. 5 is a cross sectional view of blast deflector according to another embodiment mounted on a V shaped hull;

FIG. 6 is a cross sectional view of a blast deflector according to one embodiment mounted on a bowl shaped vehicle hull;

FIG. 7 is a cross sectional view of a blast deflector mounted onto a U shaped vehicle hull;

FIG. 8 is a cross sectional view of a blast deflector mounted onto a flat surface vehicle hull; and

FIGS. 9A through 9D are the data from various blast tests showing the benefits of a blast deflector.

DETAILED DESCRIPTION

All figures and examples herein are intended to be non-limiting; they are mere exemplary iterations and/or embodiments of the claims appended to the end of this description. Modifications to system, device, the order of steps in processes, etc., are contemplated.
Referring to FIG. 1, vehicle 10 is an armored vehicle with a body 12 and an underside 13 having a hull or structure configuration 14 which may be of any shape. In this embodiment, the vehicle structure is depicted as monocoque, however, it is also appreciated that a vehicle structure may be the main frame or main body of a vehicle, such as an all terrain vehicle, an armored personnel carrier or a tank, or any other type of vehicle construction. In the shown embodiment, the vehicle is equipped with tires 15, which are through axles connected to a drive train for vehicle locomotion. Generally the vehicle underside is designed to have some blast deflecting ability so that exploding IEDs and buried mines do not incapacitate the crew or disable the vehicle.
FIG. 2A is a cross sectional view of one embodiment of a blast deflector 16. The deflector may be made of 6061-T6 steel or other metal, as well as from extruded alloys such as 5083 and 6063. Aerospace/special alloys are also viable as materials for the blast deflector and may include 7075 and 2139. The blast deflector 16 has a substantially triangular shape 18, and may be equilateral, or isosceles in configuration. Indeed, it is contemplated that the blast deflector is of any shape that is conducive to deflection of blast forces, and may be assume the shape of a triangle. In the embodiments shown, the base 20 of the deflector is configured to retrofit an existing vehicle. The sides 22, 24, may intersect at the apex 24, and may extend beyond the base to form legs 26 and 28, respectively. The legs are equipped with apertures 30, 32, respectively, to align with apertures 42 in the vehicle hull, to detachably affix the blast deflector in place on the vehicle structure. In one embodiment, apertures 42 are arranged in parallel rows along the entire length of the vehicle hull at predetermined intervals to accommodate a plurality of individual blast deflectors or an individual blast deflector having a length complimentary of the vehicle length. The blast deflector apertures may be equipped with countersinks 31, 33, respectively, to accommodate a shearable fastener 29, which may a threaded bolt 27. The fastener may be threadably engageable by mounting apparatus 25, which is engaged in apertures 42 to detachably affix the blast deflector in place on the vehicle structure. It is also contemplated that deflector may be detachably affixed to the vehicle structure by a restraint.
The blast deflector legs may also be oriented relative to each other by an angle θ chosen to compliment the vehicle hull design so that the blast deflector may accommodate a given hull shape and, when affixed thereto, impart blast deflection along the length of the deflector. The deflector is shown as being hollow, but it could also be filled with plastic, glass, composites, metals or other energy absorbing blast deflecting material. It also contemplated to be configured to have internal divisions to create individual spaces to dissipate the blast, or even be solid.
The sides of the deflector may intersect at vertex 24 which is shown as a sharp point, but which may, in other embodiments, be rounded. The sides of the deflector may straight, or they may be arcuate, with either a concave or convex orientation, as seen in FIGS. 2B and 2C, respectively.
As depicted in FIG. 2A, the base 20 may be equipped with an aperture 19 which is aligned with counterbore aperture 17 at vertex 24. It is contemplated that a sensor 11 may be accommodated within the counterbore aperture and accessible through aperture 19 of the blast deflector to transmit data regarding blast force, blast acceleration, blast velocity or any other parameter desired by the vehicle operators. It is understood that this described sensor arrangement may also be present in the blast deflector configurations of FIGS. 2B and 2C. In another embodiment, it is contemplated that a shearable fastener may extend through the aperture to the vehicle structure to detachably affix the blast deflector to the vehicle structure.
FIG. 3 is a detail view sectional of the vehicle structure underside showing apertures 42 arranged on either side 48, 50 of the vehicle structure centerline 46 at predetermined spaced intervals along its length L. While the apertures on sides 48 and 50 are parallel to each other, any arrangement of apertures may be contemplated to accommodate any arrangement of blast deflectors to the vehicle hull.
As previously mentioned, the apertures in the vehicle hull may be threaded. A shearable bolt, rivet, or other fastener may be passed through the aligned aperture 30 in the blast deflector and aperture 42 in the vehicle hull, to detachably affix the blast deflector onto the vehicle structure. As previously stated, the apertures may be equipped with mounting apparatus to detachably affix the fastener into the vehicle hull. The fasteners may be of a material designed to shear off in response to blast force, thereby permitting the blast deflector to be detached during the blast event but after it has dissipated the blast force. In some embodiments, the connection may before from friction stir welding. In some embodiments, mechanical connections are made through plates, bolts such as shear bolts, insert plates and other connecting structures. In one embodiment, insert plates are attached to the lower hull. Different bolt thicknesses and a different number of bolts in the connection can lead to different separation characteristics in a blast event, as well as different patterns of energy absorption and dissipation through bolt shearing. The bolts may have varying diameters, and may be “tuned” to shear at various forces. Bolts shearing in a controlled manner may dissipate blast energy and protect occupants in the vehicle during a blast event.
FIGS. 4 through 8 depict various blast deflectors according to several embodiments attached to different vehicle structures 14. In each embodiment, the blast deflector is placed in position on the structure to dissipate the blast energy across a wide section of the vehicle hull. The blast deflector uses a small radius approximating a sharp edge close to the ground to split the blast force of an IED , buried mine or other explosive, and direct significant energy away from the protected structure. It is understood that trading standoff for shape can be beneficial and can reduce energy transmitted into the vehicle structure. Many “V” shaped structures have a flat or radiused bottom and fail to come to a sharp point. As seen in FIGS. 4-8, the vehicle structure shapes tend to vary from flat to rounded to bowl shaped. Even if the vehicle structure is generally V shaped, the vertex of the vehicle structure's V is not sharp, but rather is rounded. The addition of the blast deflector according to the present disclosure shapes blast energy attenuation away from the vehicle structure underside, the vehicle structure itself, and the vehicle occupants. The blast deflector is detachably mounted and even if the force of the blast shears the fasteners, the blast deflector dissipates the force of the blast. The blast deflector also adds strength and rigidity, and transfers the blast energy along the entire length of the vehicle hull.
As seen in FIGS. 9A through 9D, simulated blast data showed beneficial and unexpected results because of the optimized shape, material choice, cross sections and attachment methods as described. In the simulated blast data, an IED is modeled and the blast deflector is simulated to be made of the aforesaid materials.
FIG. 9A is a graphic representation of a vehicle without a blast deflector subjected to a simulated IED blast showing the vertical acceleration over time and a test vehicle having a blast deflector according to one embodiment of the disclosure. The simulated data is filtered, and compared to a vehicle without a blast deflector. In both FIGS. 9A and 9B, the IED is oriented so the simulated blast force occurs in the center of the vehicle hull such that the blast deflector encounters a blast force approximately equally on both sides of the deflector. Specifically, in FIG. 9A, axis 52 is acceleration and axis 54 is time. Line 56 depicts the acceleration over time of a vehicle hull without a blast deflector and line 58 depicts the acceleration over time of a vehicle hull with a blast deflector. It is seen by reference to the simulated blast results that the initial acceleration of the vehicle hull without a blast deflector is expected to be much higher than that of a vehicle hull with the blast deflector. The difference in initial acceleration is important to vehicle and occupant survivability and demonstrates that the blast deflector is expected to dissipate the blast force of the IED. There is a reduction in peak acceleration and time to peak in center blast. This is reinforced by reference to FIG. 9B wherein the vertical velocity of the vehicle 60 is charted against time 62. Line 64 is the vertical velocity of an unprotected vehicle after an IED explosion, and line 66 is the vertical velocity of the vehicle with a blast deflector in place. These simulated results demonstrate that the blast deflector decreases the vertical velocity of a vehicle after an IED detonation.
FIG. 9C is a graphic representation of a vehicle subjected to a simulated IED blast showing vertical and lateral acceleration of the vehicle over time. In this test, the IED is oriented such that the blast force is offset relative to the blast deflector. Specifically, axis 68 is acceleration, and axis 70 is time. Line 72 is the is the vertical acceleration over time of the vehicle without a blast deflector subjected to an IED blast force, and line 74 is the vertical acceleration over time of the vehicle with a blast deflector that is simulated to be subjected to an IED blast. As seen in FIG. 9D, line 76 is the lateral acceleration of the vehicle without a blast deflector and line 78 is the lateral acceleration of the vehicle with a blast deflector in place. There is an expected improvement in offset blast.
The simulated data seen in FIGS. 9A-D demonstrate there is no change in vehicle structure deflection. As seen in the simulated data, the blast deflector detaches from the vehicle structure. The following simulated results are expected:

- a. Z Acceleration is expected to be reduced
- b. Center blast—shows a significant reduction; in a center blast, the blast forces are symmetrical and the deflector may remain attached to the vehicle
- c. Offset blast—shows a significant reduction

Although the steps of the above-described simulated data have been exemplified as occurring in a certain sequence, such processes could be practiced with the steps performed in a different order. It should also be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps could be omitted. In other words, the descriptions of the simulated data are provided for the purpose of illustration, and should not limit the claimed invention.
Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the disclosure. For example, embodiments of the blast deflector may be made to separate from the hull structure, or remain on the hull structure. Also, the blast deflector attachment method can be varied, so as to time the separation of the blast deflector to the hull structure earlier or later in the blast event, to achieve different energy absorbing and/or acceleration and/or velocity characteristics with different shapes, thicknesses, and material choices.
The scope of the invention should be determined with reference to the appended claims along with the full scope of equivalents. It is intended that future developments will occur, and that embodiments of the disclosed systems and methods will incorporate and be incorporated with such future developments.
Use of singular articles such as “a,” “the,” “said” together with an element means one or more of the element unless a claim expressly recites to the contrary.

Claims

1. A blast energy deflector, comprising:

a generally triangular body having a base affixed to an existing vehicle structure; the deflector having two sides that intersect at an apex; the deflector being formed with the base and the two sides as a closed form and being hollow along a length of the vehicle structure;

each the side extending beyond the base to form legs; the blast deflector configured to be detachably secured to the vehicle structure;

the legs oriented at an angle to accommodate the vehicle structure so that the deflector may accommodate the vehicle structure shape and, when affixed thereto, impart blast deflection along the length of the vehicle structure; and

wherein the legs each have a plurality of apertures, wherein each aperture has a counter sink.

2. (canceled)

3. The blast energy deflector of claim 1, wherein the triangular body is filled with plastic, glass, composites, metals or other blast deflecting material.

4. The blast energy deflector of claim 1, wherein the triangular body is configured to have internal divisions to create individual spaces to dissipate the blast.

5. The blast energy deflector of claim 3, wherein the deflector is formed as a solid due to the filled-up material.

6. The blast energy deflector of claim 1, wherein the apex is rounded.

7. The blast energy deflector of claim 1, wherein the sides are straight.

8. The blast energy deflector of claim 1, wherein the sides are arcuate.

9. The blast energy deflector of claim 1, wherein the blast deflector is configured to be detachably affixed to the vehicle structure.

10. The blast energy deflector of claim 1, wherein at least a portion of the deflector has a triangular form.

11. A vehicle with a blast energy deflector system for a vehicle structure, comprising:

at least one blast deflector having a generally triangular body with a base affixed to the existing vehicle structure;

the deflector having two sides that intersect at an apex; each the side extending beyond the base to form legs;

the legs oriented at an angle to accommodate the vehicle structure so that the deflector may accommodate the vehicle structure shape and, when affixed thereto, impart blast deflection along a length of the vehicle; and

wherein the legs each have a plurality of apertures, wherein each aperture has a counter sink,

wherein the deflector is formed with the base and the two sides as a closed form and is hollow along the length of the vehicle.

12. The vehicle with a blast energy deflector system of claim 11, wherein the blast deflector is detachably affixed to the vehicle.

13. (canceled)

14. The vehicle with a blast energy deflector system of claim 11, wherein the triangular body is filled with plastic, glass, composites, metals or other blast deflecting material.

15. The vehicle with a blast energy deflector system of claim 11, wherein the triangular body is configured to have internal divisions to create individual spaces to dissipate the blast energy.

16. The vehicle with a blast energy deflector system of claim 14, wherein the blast deflector is formed as solid due to the filled-up material.

17. The vehicle with a blast energy deflector system of claim 11, wherein the blast deflector apex is rounded.

18. The vehicle with a blast energy deflector system of claim 11, wherein the blast deflector sides are straight.

19. The vehicle with a blast energy deflector system of claim 11, wherein the blast deflector sides are arcuate.

20. The vehicle with a blast energy deflector system of claim 11, wherein a plurality of blast deflectors are affixed to the vehicle structure.

21. The blast energy deflector of claim 1, further comprising;

a lower aperture formed at vertex having a counterbore; and

a sensor accommodated within the counterbore of the lower aperture, the sensor configured to transmit data regarding at least one of blast force, blast acceleration, and blast velocity.

22. The vehicle with a blast energy deflector system of claim 11, further comprising:

a lower aperture formed at vertex having a counterbore; and