US20120174757A1

US20120174757A1 - Composite Armor Structure

Info

Publication number: US20120174757A1
Application number: US12/503,985
Authority: US
Inventors: Nabil F. Grace
Original assignee: Lawrence Technological University
Current assignee: Lawrence Technological University
Priority date: 2008-07-16
Filing date: 2009-07-16
Publication date: 2012-07-12

Abstract

A non-metallic armor structure having lightweight and being capable of withstanding multiple impacts without substantial degradation of the penetration resistance of the armor.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This utility patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/081,075 filed Jul. 16, 2008, entitled “Composite Armor Structure,” the entire disclosure of the application being considered part of the disclosure of this application, and hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to armor used for preventing the penetration of structures by projectiles. More specifically, the invention relates to an improved armor including a fiber grid structure having composite tiles, such as composite ballistic resistance tiles retained in the grid with the grids forming a substantially polyhedron structure that both increases the resistance to penetration as well as increases the performance of each individual composite tile.
Armor systems have traditionally been known to include thick metal as an outer skin to protect the structure or vehicle. Typically, these armor structures such as those used in military vehicles include layers of thick metal plates to provide resistance to the penetration of projectiles. The resistance to penetration of projectiles is very important to protect individuals inside from injury and death. Newer types of armor piercing projectiles have decreased the efficiency of metal plates in preventing projectile penetration and metal armor systems are extremely heavy, which detracts from the performance and fuel economy of mobile vehicles. The heavy weight of metal-plated armor causes many problems including limited vehicle speed, high fuel consumption, increased time for vehicle assembly, as well as detracting from the maneuverability and other operational capabilities of the vehicle. To summarize, the weight of the layered metal plates causes serious reductions in performance capabilities of any vehicle to which the armor system is added. For example, increased fuel consumption due to the heavy weight of the metal plates requires more frequent fill-ups and reduces the range of the armored vehicle. In addition, increased fuel consumption creates other problems in a military environment, such as requiring more trips to the armored vehicles by fuel tanker trucks, which are typically not armored. These fuel tanker trucks during a military operation are common targets as the armored vehicles stop operating if fuel is unable to reach them, and therefore improving the fuel economy of armored vehicles is important. In addition, the additional weight of the vehicle from the armor, when used in a military environment may seriously reduce the operating performance and characteristics of the vehicle. For example, certain vehicles when armored are incapable of traveling across some off-road terrains.
To address some of the above deficiencies with metal-plated armor, some manufacturers have replaced metal armor with lighter weight armor systems made from composite material having reinforced fibers made of, for example, Kevlar, S-2 glass, graphite, or high molecular weight polyethylene. Such armor systems have utilized these multiple layers of composite materials to achieve reduced overall weight, while yet providing sufficient structural properties that preserve the ability of the armor to protect against penetration. Many times these composite armor materials are used in combination with metal plates and can provide additional protection while yet reducing weight. It is still desirable to reduce the weight of the vehicle while yet improving the resistance of the armor to projectile penetration. These systems are very expensive and generally do not provide the desired balance between weight, cost and effectiveness.
Other armor systems have been designed that use ceramic tiles in connection with a grid to provide protection against high speed projectiles while yet minimizing the weight of the armor system. Ceramic tiles are much lighter than metal plates. Many ceramic tiles have convex surfaces and are inserted into a honeycomb grid. Upon impact by the projectile against the ceramic tiles, ceramic armor systems are known to experience failure of not only the impacted plate but also of the plates adjacent to the plate receiving the impact. Therefore, it is critical but also difficult to manage the propagation of cracks from the plate receiving the impact to adjacent plates. Ceramic tiles also typically lose structural integrity after an initial impact, making the armor system vulnerable to subsequent impacts.
The armor system must sustain multiple hits by projectiles to sufficiently protect the occupants of a vehicle. As stated above, many ceramic systems provide excellent resistance to projectile penetration against the first impact but their effectiveness is typically substantially reduced for subsequent impacts. Some manufacturers have proposed layering on top of each other multiple layers of ceramic tiles similar to the layers of metal plates previously used as well as providing layers of composite materials in combination with the ceramic tiles. These layers of composite materials are generally sheets such as sheets of carbon fiber directly engaging the ceramic tiles. While these multiple layered ceramic tiles provide additional protection, they also substantially increase the weight of the vehicle while yet experiencing propagation of cracks and debris created during impact. Propagation of cracks weakens the adjacent composite plates as well as the underlying plates. The propagation of such cracks results from the tight engagement of the armor structure and therefore while multiple layers of ceramic tiles do provide additional protection, the armor system may after an initial impact be substantially weakened against subsequent impacts.

SUMMARY OF THE INVENTION

The present invention is directed to a composite armor that improves the resistance to penetration of projectiles as well as resistance to projectile penetration from multiple impacts, while reducing the weight of the armor structure as compared to metal plate systems and other armor systems with similar penetration resistance.
More specifically, the armor system of the present invention provides a polyhedron structure which covers the surface on which armor protection is needed. The polyhedron structure is made up of a plurality of cellular structures into which composite inserts are provided. Cellular structures generally are generally a one-piece integrally formed continuous composite cellular structure of which multiple cellular structures are used to create the polyhedron structure. A filler such as a ballistic foam is provided within the polyhedron structure formed by the cellular structures. If needed, various composite laminates may be provided to provide additional protection.
Further scope and applicability of the present invention will become apparent from the following detailed description, claims and drawings. However, it should be understood that the specific examples in the detailed description are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given here below, the appended claims, and the accompanying drawings in which:

FIG. 1 is a perspective view of a cellular structure;

FIG. 2 is a plan view of the cellular structure;

FIG. 3 is a perspective view of cellular structures forming the inter-disposed sides;

FIG. 4 is a plan view of a first exemplary side in FIG. 3;

FIG. 5 is a plan view of a second exemplary side in FIG. 3;

FIG. 6 is an exploded perspective view of an exemplary polyhedron structure;

FIG. 7 is an exploded perspective view of a second exemplary polyhedron structure;

FIG. 8 is an exploded perspective view of a third exemplary polyhedron structure;

FIG. 9 is an exploded perspective view of a fourth exemplary polyhedron structure;

FIG. 10 is an exploded perspective view of a fifth exemplary polyhedron structure;

FIG. 11 is an exploded perspective view of a cellular structure without composite inserts;

FIG. 12 is an exploded perspective view of a cellular structure partially assembled to form the polyhedron structure;

FIG. 13 is a perspective view of the grid polyhedron cellular structure;

FIG. 14 is a perspective view of the cellular structure with composite plates in place and forming the polyhedron structure;

FIG. 15 is a perspective view of the polyhedron structure as complete with a portion of the sides removed to show the various layers;

FIG. 16 is a perspective view of the polyhedron structure;

FIG. 17 is an exploded partial perspective view of an exemplary polyhedron structure;

FIG. 18 is an enlarged perspective view of the polyhedron structure showing the various layers of laminate;

FIG. 19 is a two-layer polyhedron structure showing the cellular structures without composite inserts and with the sides exploded off to show the inner portions;

FIG. 20 is a perspective view of an assembled two-layer cellular structure;

FIG. 21 is a perspective view of the polyhedron structure with portions removed to show the inner foam;

FIG. 22 is a perspective view of the cellular structure with inserted ceramic tiles forming the polyhedron structure;

FIG. 23 is a perspective view of a completed polyhedron structure;

FIG. 24 is an exemplary side view of a two-layer polyhedron structure;

FIG. 25 is a side view of the two-layer polyhedron structure in FIG. 24 with ceramic tiles partially in place and partially removed;

FIG. 26 is a perspective view of a three-layer polyhedron structure showing the grid of the cellular structures;

FIG. 27 is a perspective view of the polyhedron structure with ceramic tiles in place;

FIG. 28 is a perspective view of the polyhedron structure;

FIG. 29 is a side view of the polyhedron structure in FIG. 27 with ceramic tiles partially in place and partially removed;

FIG. 30 is another exemplary side view of the polyhedron structure in FIG. 27 with the ceramic tiles partially in place and partially removed;

FIG. 31 is a perspective view of a four-layer polyhedron structure showing the grid of the cellular structure;

FIG. 32 is a first exemplary side view of a four-layer polyhedron structure;

FIG. 33 is a second exemplary side view of a four-layer polyhedron structure;

FIG. 34 is a perspective view of an exemplary two-layer polyhedron structure using rectangular side plates;

FIG. 35 is a perspective view of the polyhedron structure in FIG. 38 with the ceramic tiles inserted;

FIG. 36 is a completed perspective view of the polyhedron structure in FIGS. 34 and 35;

FIG. 37 is a perspective and top plan view of a hexagonal grid element;

FIG. 38 is a perspective and top plan view of a triangular grid element;

FIG. 39 is a perspective and top plan view of a trapezoidal grid element;

FIG. 40 is an exemplary illustration of an armored vehicle;

FIG. 41 is a perspective view of a two-layer cellular structure wherein the grids are offset relative to each other;

FIG. 42 is a top plan view of a two-layer cellular structure wherein the grids are offset relative each other; and

FIG. 43 is a side view of a two-layer cellular structure wherein the grids are offset relative to each other.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to an armor system 10 such as for the exemplary vehicle 110 illustrated in FIG. 40. The armor system 10 is partially illustrated in FIGS. 1-39 as being formed from individual polyhedron structures 20. The individual polyhedron structures 20 are generally illustrated in greater detail in FIGS. 1-39 and multiple structures of varying sizes may be required to sufficiently armor a vehicle. More specifically, the multiple polyhedron structures 20 creates individual cells that combine to form the armor system 10. Therefore, for the exemplary vehicle 110 illustrated in FIG. 40, the polyhedron structures 20 would preferably substantially cover the vehicle. To conform the armor system 10 to the vehicle, the structure of the individual polyhedron cells 20 may vary to match the contour of the vehicle. However, to reduce manufacturing costs, it is preferable to use standardized polyhedron structures whenever possible, which can be formed in single or multiple sizes to form the armor system. Therefore, the armor system 10 will be described below as being formed of multiple polyhedron structures 20, even though other shapes may be used having a cavity that is filled with a filler 100, such as ballistic foam.
The polyhedron structures 20 are generally formed of a grid of cellular structures 22. The individual cellular structures 22 may combine to form a cellular structure 30 that forms the outer surface to which laminates 80 are applied. As more specifically illustrated in FIG. 6, the cellular structure may be formed from a first face 32, a second face 34 and inter-disposed cellular sides 50. As further illustrated in FIG. 19, the cellular structure 30 may further include at least one cellular structure 40. These at least six cellular structures 22, forming the outer cellular structure 30 specifically the two faces 32, 34 and four sides 50, form a cavity into which the filler 100 is placed. The cellular structures 22 forming the outer cellular structure 30 as well as any secondary or inner cellular structures 40 or side cellular structures 50 each include a grid 38 that defines openings 36. The openings 36 are configured to receive composite inserts 70. The grid 38 extends to a border structure 39. Due to the overall size of the cellular structures 22, the grid 38 may have partial openings 37 near the border 39. These partial openings may be filled with different shaped or partial composite inserts 70.
It is preferable for the strength and integrity of the cellular structure 30 that the grid structure 38 of the sides 50 meets the grid structure 38, of the cellular faces 32, 34 structure, and if present any additional inner cellular structures 40. More specifically, the points where the grid structure 38 meets the border 39 are approximately aligned for all of the cellular structures 22. This allows the composite inserts 70 to individually support an adjacent plate and minimizes the potential for propagation of cracks from an insert 70 on the cellular structure faces 32, 34 to an insert 70 or in particular multiple inserts on the sides 50. As illustrated in the side views of other Figures, the sides within a single cellular side structure may differ, such that they match the edge pattern of one of the exterior cellular structure faces 32, 34.
Composite inserts 70 generally include a perimeter portion 72 and a first side 74 and a second side 76. Composite inserts 70 are inserted into the cellular structures 22 and in particular, into the openings 36 defined by the grid structure 38. The composite inserts 70 may be formed in triangle shapes 60, partial hexagon shapes 62, hexagon shapes 42, rectangular or square shapes 64 or any other desired shapes.
The armor system 10 further includes laminates 80 which are secured to the cellular structures 22 and the composite inserts 70. The laminates 80 are generally secured to the cellular structure 30 as well as the inner cellular structures 40 but in the preferred embodiment are not secured to the inter-disposed sides 50. While laminates 80 secured to the inter-disposed sides 50 would improve protection against projectile penetration, the laminates 80 are generally expensive and would not provide a substantial increase in protection. The laminates 80 are generally secured with the use of a binding material such as a resin to the cellular structures 22. The bonding material may also be used as a filler applied to the inserts 70 and in some cases around the perimeter portion 72 to fill in the gaps between the inserts 70 and the grid structures 38. The binder may also bind the sides 50 to the other cellular structures 30 and 40.
Laminates 80 can be formed from any material that improves the penetration resistance of the armor and more particularly, improves the resistance of the composite inserts 70 against penetration. The laminates 80 are generally shown in the Figures as being placed on at least one side of the cellular structures 22 forming the polyhedron structures in particular the exterior surfaces however, as seen in other Figures, the laminates 80 may be layered on each side of the cellular structures 22 or selectively layered to maximize resistance to penetration balanced against cost. In general, the armor 10 illustrated in the Figures uses at least two layers of laminates 80 in particularly a first layer 82 formed of a carbon fiber reinforced polymer which generally forms the exterior surface of the polyhedron structure 20 and a second layer 84 of a hybrid ductile fabric which generally engages directly against the composite inserts 70. In some cases, the binder although not illustrated may be inter-disposed between the second laminate layer 84 and the composite inserts 70. In the preferred embodiment, the exterior surface of the polyhedron structure on at least one side includes four layers of laminates particularly the first and second layers 82 and 84 layered in an alternating manner specifically including extending away from the cellular structure 22, the hybrid ductile fabric lamina 84, high modulus lamina 82, hybrid ductile fabric 84, and high modulus lamina or carbon reinforced polymer 82. In the preferred embodiment, it has been found that materials having acoustic impedance between 0.7×10⁶and 40×10⁶kg/m², as measured in a direction parallel to the normal of the laminates sheets are most effective. It should be appreciated and as disclosed in the Figures, various configurations and placements of laminates 80 may be used with the armor system 10. Adding the laminates 80 generally improves the strength against projectile resistance. Also, though not illustrated, the cellular structures 22 may form a polyhedron structure 20 with each cellular structure 22 having composite inserts being directly laminated together or laminated together with the laminates 80 inter-disposed between.
As further illustrated in the Figures specifically FIGS. 19-36, the polyhedron structures 20 may be stacked to create two, three or more layers with filler between. It is expected as shown in the Figures that for the stacked polyhedron structures 20 that only one cellular structure 40 would be placed between each filler 100 to reduce costs, although individual polyhedron structures 20 that form by itself one layer of armor may be stacked such that the cellular structures 22 with composite inserts 70 inserted in close proximity with no filler therebewteen. The sides 50 may be formed from multiple sides in stacked configuration as illustrated in the Figures, or one side cellular structure (not illustrated), extending past the inner cellular structure 40.
The composite inserts 70 may be made of materials such as ceramic, glass, metal matrix, ceramic matrix composite, or any other types of composite materials known to provide high resistance to impact penetration while providing low weight, particularly when compared to metal armor systems. The surfaces of the composite inserts 70 may vary such as having convex or concave surfaces. In addition to the other shapes described above, the composite inserts 70 may be provided in square, oval, round, or other shapes.
The cellular structures 22 may be formed in a variety of configurations but preferably use the cellular structures as described in U.S. patent application Ser. No. 11/504,343 filed on Aug. 15, 2006. Such cellular structures minimize crack propagation from a projectile impact. As described in U.S. application Ser. No. 11/504,343, the cellular structures may be formed from individual fibers that extend approximately continuous throughout the cellular structure. Of course, other fiber structures may be used without continuously extending fibers.
The filler within the polyhedron structure 20 is generally illustrated as 100 and is typically a ballistic foam or another type of lightweight filler material that is resistant to projectile penetration. The filler 100 also helps to support the composite inserts after impact from a projectile such that the initial impact of a projectile, even if it cracks the outer layer of composite inserts near the impact zone, does not completely or substantially reduce subsequent performance to additional impacts. By separating the composite inserts 70 on the cellular structure 30 with the filler 100 from the second layer of ceramic inserts shown as being inserted in the grid 40, the armor system 10 may withstand subsequent impacts from projectiles without being compromised. In addition, using a filler 100 such as a ballistic foam further increases the ability of the armor system 10 to withstand against subsequent projectile impacts.
The cellular grid structures 22 in particular the cellular structures 30, 40 and 50 of are generally also assembled as described in U.S. patent application Ser. No. 11/504,343 filed on Aug. 15, 2006. Once the individual cellular structures 22 are assembled, the polyhedron structure 20 is then assembled out of the cellular structure 30, second cellular structure 40 as well as the inter-disposed sides 50. After it is assembled into a polyhedron structure, the filler or ballistic foam 100 is inserted into the cavity of the polyhedron structure 20. In some embodiments, the polyhedron structure 20 may be assembled except one side 50 or one of the outer cellular structures 30 or 40, to allow for easy insertion of the filler 100. In other embodiments, the cellular structures 22 may be assembled but for at least one composite insert which is inserted later. To assembly multi-layer polyhedron structures, the cellular structures 22 are assembled as described in U.S. patent application Ser. No. 11/504,343 and then assembled into the polyhedron structure 20. Once the ballistic foam or filler 100 is inserted into the polyhedron structure 20, the polyhedron structure easily maintains its shape for assembly onto the armor system of a vehicle 110. The polyhedron structure 20 may be a cuboid, a rectangular box, a hexahedron, an octagonal prism, an elongated pentagonal cupola as well as any other desirable shape. As illustrated in FIG. 40, it is assembled on the vehicle 110, the cellular structure 102 having composite inserts 104 is shown in use for the floor plan 107 of a military vehicle 109. It should be appreciated that the cellular structure 102 can be assembled adjacent to each other and throughout the entire floor plan or across the entire outer surface of the vehicle. The illustrated vehicle and shape is only an exemplary embodiment and it may be used on a variety of other vehicles as well as stationary objects such as buildings and bunkers. Forming large polyhedron structures allows for lightweight building blocks to be created from which buildings may be quickly assembled for use in field operations where danger exists from projectiles. Therefore, the polyhedron structures can be transported as lightweight, easily assembled building blocks that quickly create an armored bunker structure for forward field operations. The structure would provide resistance against impact such as from mortar rounds, small arms fire, rocket propelled grenades and other projectiles. Of course, modifications can be made to the polyhedron structure 20 in particular the cellular structures 22 to provide attachment means to quickly connect the polyhedron structures together in a desired building shape.
As illustrated in FIGS. 41-43, the cellular structures 22 may be place din an offset grid 38 pattern. More specifically, when the cellular structures forming one portion of the overall cellular structure 30, may be placed together and have the grids offset, such that the grid of one structure 22 does not align with the grid of other cellular structures. Therefore, a projectile that hits the grid 38 of the outermost cellular structure, the weakest portion of the cellular structure will most likely hit a ceramic tile 70 of the underlying structure and not the grid of the underlying cellular structure. Of course, although the cellular structures are illustrated as being laminated or adjoining, ballistic foam 100 or other laminates may reside therebetween to provide enhanced resistance to projectile penetration.
The foregoing discussion discloses and describes an exemplary embodiment of the present invention. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the true spirit and fair scope of the invention as defined by the following claims.

Claims

1. An armor system comprising:

a polyhedron structure including an outer cellular structure defining individual cavities for receiving a composite insert and wherein said outer cellular structure further defines an inner cavity being substantially filled with a filler.

2. The armor system of claim 1 wherein said filler is a ballistic foam.

3. The armor system of claim 1 wherein said outer cellular structure includes at least four individual cellular structures forming at least one face and at least three sides and wherein each of said individual structures includes a border and a grid defined by said border.

4. The armor system of claim 3 wherein said grid intersects with said border at spaced intervals and wherein said intersects of said grid with said border on said face are substantially aligned with said intersects of said grid with the boarder on each of said sides.

5. The armor system of claim 3 further including an inner cellular structure and wherein said inner cellular structure is disposed a distance from said face cellular structure and wherein said filler is disposed between said inner cellular structure and said face cellular structure.

6. The armor system of claim 5 further including a second face cellular structure and wherein said second face cellular structure and said inner cellular structure define a second inner cavity and wherein said second inner cavity is substantially filled with a filler.

7. The armor system of claim 6 wherein each of said fillers are substantially free of ceramic materials.

8. The armor system of claim 5 wherein said inner cellular structure includes a plurality of inserts formed from a composite material.

9. The armor system of claim 8 wherein said composite material is a ceramic-based material.

10. The armor system of claim 1 wherein said filler is substantially free of ceramic materials and carbon fiber materials.

11. The armor system of claim 1 wherein said filler includes a foam structure.

12. The armor system of claim 1 wherein said cellular structures may be stacked together, each defining a foam-filled cavity.

13. The armor system of claim 1 further including a laminate bonded to at least one surface of said cellular structure.

14. The armor system of claim 1 wherein said outer cellular structure includes a plurality of individual cellular structures each having a grid and wherein at least two of said individual cellular structures are within approximately parallel planes and wherein the grids of each of said individual cellular structures for said cellular structures within approximately parallel planes are not in alignment.

15. The armor system of claim 1 wherein said outer cellular structure includes a plurality of individual cellular structures each including a substantially planar extent having a grid and wherein at least two of said individual cellular structures are include planar extents that are approximately aligned and wherein the grids of said aligned cellular structures are not aligned.

15. The armor system of claim 15 wherein the grid of one of said aligned cellular structures is shifted relative the grid of the other of said aligned cellular structures.

16. The armor system of claim 15 wherein the grid of one of said aligned cellular structures is shifted approximately a half a cavity relative to the grid of the other of said aligned cellular structures.

17. An armor system comprising:

a plurality of cellular structures each including a plurality of composite inserts, said cellular structures being assembled into a polyhedron shape and a filler being disposed within said polyhedron shape and wherein said filler and said composite inserts are formed from different materials.

18. The armor system of claim 17 wherein said filler has a density that is less than said composite inserts.

19. The armor system of claim 17 wherein each of said cellular structures includes a grid surrounded by a border and wherein said composite inserts are placed into openings defined within said cellular structure.

20. The armor system of claim 17 wherein said cellular structures that form opposing sides of said polyhedron shape each include a grid and wherein the grid patterns of said opposing sides of said polyhedron shape are not aligned when viewed perpendicular to the largest face of said cellular structure.

21. The armor system of claim 20 wherein the grid of one of said opposing sides of said polyhedron shape is shifted relative the grid of the other of said opposing sides.

22. The armor system of claim 21 wherein the grid of one of said opposing sides of said polyhedron shape is shifted approximately a half a cavity relative to the grid of the other of said opposing sides.