Abstract:
Methods and systems for an armor system are provided. The system includes a first face sheet and a shaped preform extending from the first face sheet. The preform includes a first edge proximate the first face sheet, a sidewall extending from the first edge to a flange extending substantially perpendicularly from the sidewall. The preform circumscribes an area of the first face sheet. The system also includes a tile of armor material complementarily-shaped to fit within the area circumscribed by the preform. The tile is positioned within the preform such that at least a portion of the tile is between the first face sheet and the flange. The system includes a second face sheet covering the preform and the tile on a side opposite from the first face sheet.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH &amp; DEVELOPMENT 
       [0001]    The invention was made with Government support under Contract Number W911NF-05-2-0025 awarded by the Army. The Government has certain rights in this invention. 
     
    
     BACKGROUND 
       [0002]    Embodiments of the disclosure relate generally to composite armor laminates and more particularly, to methods and systems for fabricating composite armor laminates. 
         [0003]    At least some known armor systems include a dense ceramic tile enclosed in a supporting structure such as a composite sheet material. The ceramic tile is positioned within the supporting structure to receive ballistic missiles and substantially prevent the missile from passing through the armor system and into an occupied cabin of the vehicle. During impact, one or more tiles may be directly impacted by the missile and other adjacent tiles not directly impacted by the missile may impart forces onto adjacent tiles. A composite spacer positioned between the tiles may limit the amount of damage to the adjacent tiles by absorbing at least a portion of the forces imparted by the tiles that were directly impacted by the missile. During assembly of the armor system, the composite spacer is positioned between tiles manually during layout of the armor system components. This process is time consuming and manual labor intensive. 
       SUMMARY 
       [0004]    In one embodiment, an armor system includes a first face sheet and a shaped preform extending from the first face sheet. The preform includes a first edge proximate the first face sheet, a sidewall extending from the first edge to a flange extending substantially perpendicularly from the sidewall. The preform circumscribes an area of the first face sheet. The system also includes a tile of armor material complementarily-shaped to fit within the area circumscribed by the preform. The tile is positioned within the preform such that at least a portion of the tile is between the first face sheet and the flange. The system includes a second face sheet covering the preform and the tile on a side opposite from the first face sheet. 
         [0005]    In another embodiment, a method of forming a ballistic resistant armor laminate includes providing a first face sheet and at least one of forming an integral preform with the first face sheet and coupling a shaped preform to the first face sheet wherein the preform extends from a face of the first face sheet to a distal edge and wherein the preform circumscribes an area of the face. The method also includes positioning a tile of armor material within the area circumscribed by the preform, forming a flange from the distal edge of the preform wherein at least a portion of a toe of the flange extends substantially parallel to the face and covers at least a portion of the tile, and coupling a second face sheet to the flange to such that the preform and tile are sandwiched between the first and second face sheets. 
         [0006]    In yet another embodiment, an armored vehicle includes a vehicle hull and an armor system covering at least a portion of the hull. The armor system includes a plurality of face sheets parallelly oriented with respect to each other and a shaped preform extending from a face of a first of the plurality of face sheets to a face of an adjacent second of the plurality of face sheets, the preform joining the first and the second face sheets. The vehicle also includes a plurality of tiles of armor material sandwiched between the first and the second sheets and the preform. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of an exemplary preform in accordance with an embodiment of the present invention; 
           [0008]      FIG. 2  is a perspective view of a partially assembled armor system that may be used with preform shown in  FIG. 1 ; 
           [0009]      FIG. 3  is another perspective view of partially assembled armor system shown in  FIG. 2 ; 
           [0010]      FIG. 4  is a longitudinal cross-section view of a segment of preform that may be used with system shown in  FIG. 2 . 
           [0011]      FIG. 5  is a perspective view of the exemplary armor system shown in  FIGS. 1-4 ; and 
           [0012]      FIG. 6  is a perspective view of a light weight high mobility vehicle that includes a hull. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The following detailed description illustrates the disclosure by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the disclosure, describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, including what is presently believed to be the best mode of carrying out the disclosure. The disclosure is described as applied to a preferred embodiment, namely, a process of forming composite armor laminates. However, it is contemplated that this disclosure has general application to manufacturing components and assemblies where materials may be joined to form larger subsystems of panels and/or sheets that heretofore required significant manual labor to assemble. 
         [0014]      FIG. 1  is a perspective view of an exemplary preform  100  in accordance with an embodiment of the present invention. Preform  100  includes a sidewall  102  that is configurable to a plurality of different shapes. Preform  100  is illustrated in  FIG. 1  in a hexagonal shape, but any shape or amorphous contour is contemplated. Perform  100  is formed in a closed configuration such that a cell  104  is circumscribed by preform  100 . Preform  100  may include a single cell  104  or may include a plurality of cells. In the exemplary embodiment, cells  104  are sized and shaped complementary to a predetermined size and shape of a tile of armor material to be received therein. In one embodiment, preform  100  is formed from a web of material in a desired shape. In other embodiments, preform  100  is formed from a continuous composite fiber wound through a form or mandrel (not shown) having the desired shape. A number of passes or turns of the continuous composite fiber that are channeled through each leg of the cell is determined based on a force absorption or strength requirement of the preform. The continuous composite fiber may comprise, but is not limited to a carbon fiber, a fiber glass fiber, an aromatic polyamide fiber such as Aramid™, other fiber filaments or combinations thereof. The continuous composite fiber may also comprise, but is not limited to, a thread, a tow, or a web comprising the above materials. The fiber, web, or tow may be impregnated with an adhesive, a thermoplastic, or a thermoset. 
         [0015]    In the exemplary embodiment, sidewall  102  includes a first edge  106 , a second edge  108 , and a sidewall  110  extending therebetween. In the exemplary embodiment, each of edges  106  and  108  include a flange  112  extending substantially perpendicularly away from sidewall  110 . In various embodiments, flange  112  comprises a single toe extending from one or both of edges  106  and  108 , in other embodiments, flange  112  comprises a pair of toes extending in opposite direction from one or both of edges  106  and  108 . 
         [0016]    In the exemplary embodiment, preform  100  is a rigid free-standing body. In other embodiments, is a fiber or fabric form that is flexible. The fiber or fabric may comprise dry carbon, carbon fiber impregnated with an epoxy or resin, or various combinations thereof. 
         [0017]      FIG. 2  is a perspective view of a partially assembled armor system  200  that may be used with preform  100  (shown in  FIG. 1 ). System  200  includes a face sheet  202  that includes a length  204 , and width  206 , and a thickness  208 . Although illustrated in  FIG. 2  as being substantially rectangular, face sheet  202  may be any shape including regular and irregular shapes. In the exemplary embodiment, preform  100  is integrally formed with face sheet  202 . Preform  100  is woven with face sheet  202  or is otherwise formed with face sheet  202 . Face sheet  202  may comprise woven carbon fibers, carbon fiber sheet or fabric. Face sheet  202  may comprise dry fabric for infusion of resin or epoxy using a vacuum process such as but not limited to a vacuum-assisted resin transfer molding (VARTM) process. Face sheet  202  may also include a fiber such as carbon pre-impregnated with for example but not limited to resin, epoxy or combinations thereof. 
         [0018]    System  200  includes one or more armor tiles  210  within cells  104  in complementary mating engagement. In the exemplary embodiment, cells  104  are substantially hexagonal in cross-section and tiles  210  are also substantially hexagonal in cross-section. Tiles  104  are positioned within cells  104  until all cells are filled with tiles  210 . In the exemplary embodiment, armor tiles  210  comprise a ceramic material for example, but not limited to boron carbide, silicon carbide, aluminum oxide, and titanium boride. Each armor tile  210  includes perimeter surface portions  212  for mating juxtaposition with perimeter surface portions  212  of adjacent armor tiles  210  through the segments preform  100  that lie between the perimeter surface portions  212  to provide a composite layer of armor capable of withstanding and dissipating large forces, for example, upon ballistic impact and shattering of an adjacent tile. Separation of adjacent tiles  210  by preform  100  facilitates absorption of forces transmitted toward an adjacent tile and facilitates dispersing the forces towards other tiles. 
         [0019]      FIG. 3  is another perspective view of partially assembled armor system  200  (shown in  FIG. 2 ). In the exemplary embodiment, system  200  includes a second face sheet  300  coupled to preform  100 . Second face sheet  300  is substantially similar to first face sheet  202 , however second face sheet  300  may include differences from first face sheet  202  in various embodiments. For example, in one embodiment, described above, preform  100  is formed integrally with first face sheet  202 . Moreover, face sheets  202  and  300  may comprise different materials to permit optimum performance for their respective roles. For example, face sheet  202  may be exposed to weather or the elements to a greater degree than face sheet  300  because of the orientation of system  200  on a vehicle. Face sheet  202  may require a greater UV, abrasion, and chemical resistance than face sheet  300 . In the exemplary embodiment, face sheet  300  is coupled to preform  100  through flanges  112  extending from second edge  108  using stitching  302 . In another embodiment, face sheet  300  is coupled to flanges  112  using an adhesive. 
         [0020]      FIG. 4  is a longitudinal cross-section view of a segment  400  of preform  100  that may be used with system  200  (shown in  FIG. 2 ). In the exemplary embodiment, preform  100  includes first edge  106 , second edge  108 , sidewall  110 , and flanges  112 . Tile  210  is positioned in abutting relationship with sidewall  110  (gap shown in  FIG. 4  for clarity) such that a portion of tiles  210  are covered by flanges  112 . Sidewall  110  tends to provide cushioning and force dissipation between adjacent tiles  210 . Flange  112  is flexible at second edge  108  such that during installation of tile  210 , flange  112  is positioned vertically and when tile  210  is positioned within cell  104 , flange  112  is folded perpendicular to sidewall  110  to cover a portion of tile  210 . Second face sheet  300  is then coupled to flange  112  using, for example, stitching, or adhesion. 
         [0021]    During assembly, perform  100  may be substantially rigid or semi-rigid to facilitate positioning tiles  210  within cells  104  automatically using a pick-and-place machine including for example, a robotic arm. After positioning tiles  210  within cells  104 , flange  112  is folded down to be substantially flush with tiles  210 . Second face sheet  300  is then stitched or otherwise attached to flange  112 . If face sheets  202  and  300 , and preform  100  are fabricated from dry composite material, system  200  is further infused with a resin or an epoxy using a vacuum process such as, but not limited to a vacuum-assisted resin transfer molding (VARTM) process. In another embodiment, face sheets  202  and  300 , and preform  100  may be formed of a fiber such as carbon pre-impregnated with, for example, but not limited to resin, epoxy or combinations thereof. Further processing includes curing the impregnated carbon components. 
         [0022]      FIG. 5  is a perspective view of an exemplary armor system  200 . After curing, face sheets  202  and  300 , preform  100 , and tiles  210  form a rigid composite armor laminate, which may be cut or machined to further match desired dimensions. 
         [0023]      FIG. 6  is a perspective view of a light weight high mobility vehicle  600  that includes a hull  602  mounted on a series of driven wheels  604  or tracks, and turret  606  on hull  602 . Hull  602  is constructed of steel armor plate  608 . Composite armor laminate system  200  may be formed to a specific contour of a specific vehicle of area on a vehicle. In the exemplary embodiment, system  200  provides energy absorption from detonation of an explosive missile on an adjacent armor tile through preform  100 . Forces applied to tiles adjacent to tiles  210  may be moderated by energy transfer to adjacent tiles through preform  110 . 
         [0024]    The above-described methods of fabricating composite armor laminate structures are cost-effective and highly reliable. The methods and systems include using a composite preform to facilitate reducing hand labor during the assembly process. The preform includes composite fabric or thread that when cured provides strength, absorption of forces between tiles and redirection of forces between tiles to transmit forces over a wider area. Accordingly, the methods and systems facilitate assembly of composite armor laminate systems in a cost-effective and reliable manner. 
         [0025]    While embodiments of the disclosure have been described in terms of various specific embodiments, those skilled in the art will recognize that the embodiments of the disclosure can be practiced with modification within the spirit and scope of the claims.