Abstract:
An armor panel for protection from a projectile having a movement spinning axis. The panel comprises armor strips attached to each other, a front face for facing the projectile, and a rear face for facing away from the front face. The strips are arranged so that at least a majority thereof is oriented transversely to at least the front face. The strips are connected to each other so that a static friction force Fs 1  needs to be applied to at least partially disconnect them, and/or material from which at least some strips are made is such that a static friction force Fs 2  needs to be applied to at least partially disconnect a portion thereof. At least during penetration of the projectile into the panel, a dynamic friction force between the projectile and the strips exceeds, under the respective condition, at least one of the Fs 1  and Fs 2.

Description:
FIELD OF THE INVENTION 
       [0001]    This subject matter of the present application relates to light weight armor for ballistic protection of people and vehicles. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is known in the art to use laminated and/or layered armor panels in order to protect a body from an incoming projectile. Usually, such a laminated armor panel comprises a plurality of layers whose number and characteristics are chosen according to the expected ballistic threat including the parameters of projectiles which the armor is designed to protect the body from. 
         [0003]    It is also known to use armor panels by arranging them at an angle to the direction from which a projectile is expected to approach a surface to be protected (which is normally considered to be perpendicular to that surface), thereby causing deflection of the projectile upon impact on the armor. 
         [0004]    The following table (Table 1) provides acronyms and abbreviations used in the present application. 
         [0000]    
       
         
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Short Description 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 AP 
                 Armour Piercing 
               
               
                   
                 CNT 
                 Carbon Nano Tube 
               
               
                   
                 EFP 
                 Explosively Formed 
               
               
                   
                   
                 Projectile 
               
               
                   
                 FGM 
                 Functional Graded 
               
               
                   
                   
                 Materials 
               
               
                   
                 FSP 
                 Fragment Simulation 
               
               
                   
                   
                 Projectile 
               
               
                   
                 NP 
                 Nano Particles 
               
               
                   
                 SiC 
                 Silicon Carbide 
               
               
                   
                 SiSic 
                 Silicon/Silicon Carbide 
               
               
                   
                   
               
             
          
         
       
     
       SUMMARY OF THE INVENTION 
       [0005]    Accordnig to one aspect of the subject matter of the present application, there is provided an armor panel configured for protecting a body from an incoming projectile having a movement axis and configured for spinning about said axis, said armor panel comprising a plurality of armor strips attached to each other, said panel having:
       a front face configured for facing the projectile; and   a rear face configured for facing away from the front face;       
 
         [0008]    wherein said strips are arranged within said armor panel so that at least a majority thereof are oriented transversely to at least said front face of the armor panel, 
         [0009]    wherein at least one of the following conditions applies:
       (i) the strips are connected to each other so that a static friction force Fs 1  needs to be applied in order to at least partially disconnect them; and   (ii) the material from which at least some of the armor strips are made is such that a static friction force Fs 2  needs to be applied in order to at least partially disconnect a portion thereof from its remainder; and       
 
         [0012]    wherein the armor panel is configured so that at least during penetration of the spinning projectile into said armor panel, a dynamic friction force between the spinning projectile and said strips exceeds at least one of said Fs 1  and Fs 2 , under at least one of the respective condition (i) and (ii). 
         [0013]    More particularly, the armor strips can be attached to each other such that in penetration of the spinning projectile through the armor panel, each armor strip is configured for adhering to the projectile with a greater adherence force that to its neighboring armor strips. In other words, the bonding of the armor strips is such that in penetration of the spinning projectile into the armor panel, the dynamic friction force between the projectile and the armor strips exceeds the static friction force between neighboring armor strips. 
         [0014]    Additionally, or alternatively, within a single, armor strip, the material of the armor strip can be chosen such that in penetration of the spinning projectile through the armor panel, the material is configured for adhering to the projectile with a greater adherence force than to neighboring areas of same material. In other words, the material is such that in penetration of the spinning projectile into the armor panel, the dynamic friction force between the projectile and particles of material of the single armor strip exceeds the static friction force between the particles of the material within the single armor strip. 
         [0015]    The armor strips can be made out of a material having a high tensile strength. The term ‘high tensile strength’ refers here to a tensile strength which is at least 1 GPa, more particularly at least about 2 GPa, even more particularly at least about 5 GPa, and still more particularly at least about 10 GPa. Furthermore, the armor strips can be made of a material having a high weight to tensile strength ratio. 
         [0016]    The armor strips can be fully made out of a continuous material, for example a gel like or a plasticine-like material. Alternatively, the armor strips can comprise fibers. 
         [0017]    Provided below are several examples of materials and fibers, that can be used in the armor panel according to the presently disclosed subject matter, along with a denomination of exemplary values of their tensile strength: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Material 
                 Tensile strength (GPa) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Kevlar ® 
                 3.6 
               
               
                   
                 Dynema ® 
                 ≈3 
               
               
                   
                 Aramid 
                 3.5 
               
               
                   
                 Carbon nano-tubes 
                 10 
               
               
                   
                   
               
             
          
         
       
     
         [0018]    In a particular example, the armor strips can be made of a nano particles (NP) based material. In particular, nano particles such as TiS2, WS2, or Carbon Nano Tube (CNT), can be used, which have extremely high strength (for example, ten times higher than steel), very high stiffness, low density, good chemical stability and high thermal and electrical conductivities. 
         [0019]    Additional features of the armor strips and of the material used for their manufacture can be:
       The armor can have a CNT nano structure (Graphene like) with high surface/volume ratio.   The fibers comprising the nano particles can be of a length of a few millimeters each. This can be advantageous for high performance fibers and composites.   When bonded together using adhering, the armor panel can include a matrix material made, for example, of an epoxy, a modified epoxy, or a resin. The matrix material itself can also include nano particles.   Adding NP to a matrix, for example a polymeric matrix, can result in better ballistic performance. It has been found that reinforcing NP with such matrix can increase the strength and modulus (Young) thereof.   The NP, for example CNT , WS2 or TiS2 are embedded in a matrix in such a way that enhance the mechanical properties.   The armor member or armor system, which are for use against AP and EFP threats and are made of NP or CNT-Based FGM Nano-Composites, can have a reduced total areal density when compared with known armor members or systems. In addition, these materials have extremely high tensile strength (ten times higher than steel), very high stiffness, low density, good chemical stability and high thermal and electrical conductivities;   The nano-particles can be relatively long compared to other nano particles—in the range of 1-2 mm long;   The CNT fiber can include single, double and multi-wall CNT, or a combination thereof.       
 
         [0028]    One advantage of using the nano-fibers referred to above is that, surprisingly enough, it is a unique behavior under which the strength of the armor strip made of such fibers does not change with knots compared to all other fibers tested in the same technique. Such a unique behavior could affect the final composites structure properties and eventually ballistic performance. The nano-fiber is stronger, lighter, safer, and more energy efficient composite products for high performance armor and armor systems. 
         [0029]    Another advantage of nano-fibers is that they can provide the armor strips with mechanical properties greater than those used in the industry today. For example compared to regular carbon fibers the elongation of nano-fibers can be 10 times greater, the strength is doubled, the elastic modulus is 3 times greater and the density is lower than 1 gr/cm3 which makes it a light weight material. 
         [0030]    It is a special feature of the subject matter of the present application, that the strips are oriented transversely to at least the front face of the armor panel. This orientation will be explained in more detail below, and it should be noted in this connection that in the present application, the term “strip” means a piece of material having two parallel upper and lower surfaces of a length L and a width D, and a thickness t between said surfaces, which meet a condition that the length and the width of the strip are essentially greater than its thickness. 
         [0031]    Having the above dimensions, the strips are oriented in the panel so as to have:
       a face rim of the length L and thickness t;   a side rim of the width D measured along the strip surfaces in the direction perpendicular to the length L; and   the thickness t measured in the direction perpendicular to said strip surfaces.       
 
         [0035]    Since the armor strips can have two strip surfaces, its face and side rims have two edges formed by the intersections of the rims with the two surfaces. 
         [0036]    The armor strips can be stacked in the armor panel and attached to each other by at least one of the following:
       electrostatic bonding;   weaving;   knitting; and   adhering (using an adhesive).       
 
         [0041]    When bonded to each other to form the armor panel, at least a majority of the face rims of said armor strips can be aligned with one another, e.g. so as to lie in a plane parallel to or coinciding with the front face of the armor panel. The same can be correct with respect to the strips&#39; rear rims. Consequently at least a majority of the side rims of said armor strips will be aligned with one another, e.g. so as to line in a plane parallel to or coinciding with the panel&#39;s side which is perpendicular to the front face of the panel. 
         [0042]    As a result, the armor panel can have the following dimensions:
       a width W measured along the front face of the panel, which is equal to the length L of the face rim of the armor strips;   a height H also measured along the front face of the panel, which is calculated based on a combined thickness T of the thicknesses t of the stacked armor strips; and   a thickness M which is measured in the direction perpendicular to the front face of the panel, and is equal to the length D of the side rim of the armor strips.       
 
         [0046]    With the above arrangement, in a cross-section of the armor panel taken along a plane perpendicular to the front face thereof, the side rims of the length D have a real-length projection on the cross-sectional plane. 
         [0047]    In case fibers are used, the arrangement can be such that in some armor strips the fibers are oriented along the longitudinal dimension of the armor strips, i.e. along dimension L, and in other armor strips, the fibers are oriented along the width dimension, i.e. along dimension D. Such a design can form a bi-directional criss-cross pattern of fibers, facilitating more efficient ballistic resistance of the armor panel. 
         [0048]    According to a specific example, the armor strips can be oriented within the armor panel at a slanted orientation, so that the side rims are at an angle to a plane perpendicular to the front face of the panel, and containing the intersection line between the armor strip and the front face. In other words, in the above cross-section, the armor strips appear angled to the front face. 
         [0049]    Thus, the armor strips are also slanted with respect to the expected approach direction of incoming projectiles against which the armor panel is configured to protect. The slanting angle of the armor strips can depend on the specific use of the armor panel. According to different examples, the slanting angle can be up to about 80°, more particularly up to about 70°, even more particularly up to about 60°, and still more particularly up to about 45°. 
         [0050]    The armor strips can be flexible and/or pliable. The armor panel can be rigid or flexible. It can have, in addition to the stacked-strips body, a front and/or a backing layer, which can further be a part of a wrapping forming an exterior enclosure for the stacked-strips body. 
         [0051]    The armor panel can be configured to be, in assembly, free of any rigid armor elements. Examples of such elements can be layers made of steel/ceramic/metal etc. 
         [0052]    According to another aspect of the subject matter of the present application there is provided a method for producing an armor panel of the previous aspect, said method comprising: 
         [0053]    a) providing a plurality of armor strips, each strip having:
       a face rim of length L;   a side rim of width D, defining together with said face rim a strip surface; and   a thickness t measured in a direction perpendicular to said strip surface.       
 
         [0057]    b) attaching said plurality of armor strips to one another such that at least a majority of face rims of the strips are aligned with one another to form a face; 
         [0058]    wherein, the armor panel produced by said method has a front face constituted by the aligned face rims of the armor strips, and wherein the width of the front face is equal to the length L of the face rim, and height of the front face is equal to the combined thickness T of the thicknesses t of the armor strips. 
         [0059]    In operation of the armor panel and during penetration of the spinning projectile into it, due to the fibrous nature of the armor strips, the fibers adhere to the projectile, while being locally detached from their neighboring fibers, and become knotted together. Thus, the spinning projectile becomes entangled and trapped within the fibrous material, thereby considerably reducing the kinetic energy of the projectile. 
         [0060]    In addition, the fibers can have a tensile strength high enough to considerably slow down the spinning projectile as it attempts to progress within the fibrous material together with the fibers entangled thereabout. 
         [0061]    Furthermore, the slanting of the armor strips, can cause the projectile impacting the armor panel to become deflected from its initial (straight) movement axis due via a ricochet process. In such case, due to the slanting and certain asymmetries, the projectile is caused to travel along an arc (not a straight line), thereby deflecting it from the body to be protected. The ricochet can even be such that the projectile exits the armor panel without even impacting the body to be protected. 
         [0062]    The design of the armor panel of the present application thus affects the trajectory of the incoming projectile, and controls the impact energy on the body to be protected, so that the concept is that there is no reason to defeat a threat but rather to avoid it. 
         [0063]    The above design can be adopted for a helmet protection system where the conventional concept could not defeat AP threats, since the residual energy from the impact of the projectile could generate lethal impact to the solider&#39;s head. Under the present design, AP threats will be deflected from the protective helmet with no or little residual energy to affect the head of the soldier. Such quantum leap technique could pave the way for the first AP protection helmet. 
         [0064]    The same basic new concept can be adapted for personal armor where one can use the fibrous material in order to develop real flexible armor which can stop AP threats level. A similar approach can be used for vehicle armor, etc. 
         [0065]    It is estimated that armor of the type described above which is configured for use against EFP threats and AP threats, where one uses only the nano composite as a deflector fully acting as a single member of add-on-armor, this can result in a weight reduction of about 20% compared to current armor solutions. 
         [0066]    According to a specific use of the armor panel, it can constitute a spall liner, front layer or backing layer, i.e. working in conjunction with additional ballistic layers of material to form an armor system. 
         [0067]    The armor system can comprise a hard front layer (i.e. a layer facing the direction of an expected threat) configured to damage a threat and a back layer configured to absorb the residual energy of the threat after it has impacted the front layer. 
         [0068]    The armor panel of the present application can be used either as an add-on armor mounted on a structure, vehicle etc. Alternatively, it may be used as a personal armor such as, for example, vests, helmets etc. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0069]    In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
           [0070]      FIG. 1A  is a schematic is a schematic isometric view of an armor panel according to the subject matter of the present application; 
           [0071]      FIG. 1B  is a schematic front view of the armor panel shown in  FIG. 1A ; 
           [0072]      FIG. 1C  is a schematic exploded isometric view of two armor strips used in the armor panel shown in  FIG. 1A ; 
           [0073]      FIG. 1D  is a schematic cross-sectional view of an armor panel according to another example of the present application; 
           [0074]      FIG. 2  is a schematic stress-strain diagram of the material of the armor panel shown in  FIG. 1A ; 
           [0075]      FIGS. 3A to 3D  are schematic frequency/strength diagrams of various materials used for the manufacture of the armor panel of the present application; 
           [0076]      FIG. 4  is a photograph of an enlarged portion of a CNT material used in the manufacture of the armor panel of the present application; 
           [0077]      FIG. 5  is a schematic cross-sectional illustration of the armor panel shown in  FIG. 1A , when penetrated by a spinning projectile; and 
           [0078]      FIG. 6  is a schematic illustration of a process for the manufacture of fibers used in the production of the armor panel shown in  FIGS. 1A to 1D . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0079]    With reference to  FIGS. 1A to 1D , a laminated armor panel is shown generally designated as  1 . The armor panel  1  is constituted by a plurality of armor strips AS, the strips being attached to each other. Each of the armor strips AS is made of fibers  6 . 
         [0080]    Each armor strip AS has a strip surface of a length L and a width D, wherein the length L is considerably greater than the width D, i.e. L&gt;&gt;D. Each of the armor strips AS also has a thickness t, measured in a direction perpendicular to the strips surface, t being considerably smaller than both D and L, i.e. t&lt;&lt;D, L. 
         [0081]    With particular reference being drawn to  FIG. 1C , two different armor strips AS are used in order to form the armor panel  1 , a D strip  2  in which the fibers are arranged along the direction of the width D, and an L strip in which the fibers are arranged along the direction of the length L. 
         [0082]    Each of the strips  2 ,  4  has a face rim of length L. The face rim  5  of the D strip  2  is constituted by the combination of cross-sections of the fibers  6  used to form the D strip, whereas the face rim  7  of the L strip  4  is constituted by the length of the outermost fiber  6  constituting the L strip. 
         [0083]    As observed from  FIGS. 1A and 1B , the D and L layers  2 ,  4  are disposed one on top of the other, in a stacked manner, so that the face rims  5 ,  7  of the armor strips  2 ,  4  are aligned with one another. 
         [0084]    The armor strips  2 ,  4  can be simply stacked one on top of the other, but can also be physically attached to each other by such means as: electrostatic connection between the layers, weaving, stitching and bonding using an adhesive matrix (not shown). 
         [0085]    As a result, the armor panel  1  is formed with a front face (also referred to as strike face) SF which is constituted by the face rims  5 ,  7  of the armor strips  2 ,  4 . The armor panel  1  (see  FIG. 1 ) has the following dimensions:
       a width W, measured along the length of the armor strips  2 ,  4 , which is equal to the length L of the face rims  5 ,  7 ;   a thickness M, measured along a dimension perpendicular to the front face, which is equal to the width D of the armor strips  2 ,  4 ; and   a height H, measured along the third dimension, in a direction perpendicular to width W and thickness M, which is equal to a combined thickness T of the thicknesses t of the armor strips.       
 
         [0089]    Using different types of armor strips  2 ,  4  facilitates increasing the ballistic resistance of the armor panel  1  by forming a criss-cross pattern (when viewed perpendicular to the surface of the armor strips AS. 
         [0090]    It is observed that in the armor panel  1 , the armor strips  2 ,  4  are arranged such that they are oriented transverse to the impact direction of the projectile PJ. In other words, in a cross-section taken along a plane perpendicular to the front face SF of the armor panel  1  along the height H of the panel  1 , the armor strips  2 ,  4  are seen oriented transverse to the front face SF (see left side view in  FIG. 1A ). 
         [0091]    In the above example, the armor strip  2 ,  4  are transverse to the front face SF and are oriented at an angle of 90° thereto (i.e. perpendicular). However, this does not necessary have to be the case as will now be discussed with respect to  FIG. 1D . 
         [0092]    With reference to  FIG. 5 , in operation, the incoming projectile PJ (e.g. a bullet) is configured for spinning rapidly about its own axis. Thus, upon penetration into the armor panel  1 ,  1 ′, the projectile PJ attempts to “screw” itself into the armor panel, and more particularly, makes its way through the criss-cross pattern of the armor strips  2 ,  4 . 
         [0093]    When the projectile PJ attempts the above, the dynamic friction force FD between the spinning projectile PJ and the fibers  6  of the armor panel  1 ,  1 ′ is greater than the static friction force FS 2  between the fibers  6  themselves, or than the static friction force FS 1  between neighboring armor strips  2 ,  4 . 
         [0094]    As a result, the fibers  6  “adhere” to the projectile PJ, and due to its spinning about its axis, become tangle and knotted up with each other. In other words, since the fibers ‘adhere’ to the spinning projectile, they become ‘wrapped’ around it life on a spinning spool. 
         [0095]    In the above process, the tensile strength of the fibers plays an important role. Due to the high tensile strength of the fibers  6 , the projectile PJ is required to spend more and more energy both on progressing within the knotted and tangle portion of the armor panel  1 ,  1 ′ and on spinning. This progression through the knotted fibers accounts for absorption of a considerable amount of the kinetic energy of the projectile PJ. 
         [0096]    With reference to  FIG. 1D , another armor panel is shown generally being designated as  1 ′, and also comprising a plurality of armor strips  2 ,  4 , similarly to the previously described armor panel  1 . 
         [0097]    However, contrary to the armor panel  1 , in the armor panel  1 ′ the armor strips are oriented an a slanting angle with respect to the front face SF. According to this specific example, the angle is θ=45°. 
         [0098]    Thus, in addition to the previously described penetration process of the projectile into the armor panel  1 , in the present example, due to the slanting, the projectile PJ changes its trajectory, at least at first, to become aligned with the direction of the armor strips (i.e. deflecting it by 45°). Thereafter, due to its spinning and inertia, and owing to asymmetric forces, the projectile PJ can continue being deflected so that it essentially moves along an arc instead of along a straight line (i.e. ricocheting from the armor panel). This ricocheting can cause the projectile to exit the armor panel  1 ′ even without impacting the body to be protected (not shown). 
         [0099]    The materials from which the fibers  6  of the armor strips  2 ,  4  are made are chosen to have a very high tensile strength (up to 10 GPa). For example, the material can be a Carbon Nano Tube (CNT) material (see  FIG. 4 ). In addition, these materials are configured for better adherence to the incoming projectile than to neighboring fibers  6  or neighboring armor strips. 
         [0100]    It is also noted that in manufacture of armor strips from various materials, e.g. Kevlar®, Dynema etc. knots can be formed by the fibers constituting the material. With reference to  FIGS. 3A to 3D , it is observed that, as opposed to the above materials, the strength of the CNT material does not deteriorate as a result of such knots (partly for the explanation above regarding the mechanism of penetration of the projectile PJ). 
         [0101]    With reference to  FIG. 2 , a schematic stress-strain of CNT fibers used in the armor strips  2 ,  4  of the armor panel  1 ,  1 ′ is shown, compared to Kevlar®. It is observed that whereas the Kevlar® reaches its breaking point about 2%, the CNT fibers reach a surprisingly high value of 6.5% and even more. 
         [0102]    Different processes can be used for the manufacture of the fibers  6 . In particular, with reference to  FIG. 6 , CNT fibers can be manufactured using a CVD based process where Carbon Nano tubes (CNT) are created to form a sort of an Aerogel inside a reactor. The aerogel is then pulled and collapsed to form CNT (see  FIG. 4  in which a double-wall CNT is shown). An illustration of the process appears in  FIG. 6 . A similar process is described in U.S. Pat. No. 7,323,157. 
         [0103]    The uniqueness of this process is that it is continues allowing the fabrication of a theoretically unlimited long fiber. The transit from a fiber made of CNT to a GNF is possible in the last stage of the fiber pulling where external interference causes the double walled CNT&#39;s to collapse forming closely packed Graphene sheets. 
         [0104]    It is by understanding the fabrication of the GNF, the characterization is made possible in a short time. The impurities and inconsistencies in the material are linked to various process parameters which could be controlled, changed and optimized. 
         [0105]    For example, in the early stages of the reaction, nano particles of iron are formed to serve as catalysts for the formation of CNT&#39;s. Excess amounts the precursor used to form the iron nano particles could result in the formation of iron agglomerates within the GNF.) 
         [0106]    There are many other parameters which could be controlled and characterized by various characterization methods: 
         [0107]    HR-SEM—A HR-SEM (Zeiss Ultra+): It is visible from preliminary images taken to evaluate the material ( FIG. 6 ) that the data which is collected from those images is of great importance for material implementation as composite material. The impurities are also visible as well as amorphous carbon (if it exists). In order to verify the impurities composition, an EDS detector is used. There is an EDS detector operating on the HR-SEM with an image analysis software. 
         [0108]    TEM—A FEI Titan 80300 electron microscope can be used to view the composition of the nano Graphene tubes, the number of walls the CNT had prior to collapsing, the quality and relative quantity of collapsed tubes to tubes which did not collapse. 
         [0109]    The main mechanical characterization method for a single fiber would be the FAVIMAT testing machine. Single fiber testing via instruments such as the FAVIMAT proves of use to this research since limited testing material is available Single fiber testing with the Favimat allows testing of fineness (linear density), strength, and elongation. As single fiber testing is performed the distribution of properties in a sample can be readily obtained. An example for the curve obtained from FAVIMAT is shown in  FIG. 2 . Single fiber tensile testing is compared to more traditional bulk testing which uses bundles of fibers, such as DMA testing for yarns (bundles of fibers interlocked together). 
         [0110]    All parameters will be collected from those tests will be used to successfully model the fiber for computerized simulation as well as to compare with commercially available fibers. 
         [0111]    The characterization of the composite material will begin with the process of sample preparation. The fabrication method of the composite samples will strongly depend on the polymeric matrix and its properties. For example the matrix material could well be Epoxy in which case injection or casting methods will be considered. Another option for the matrix material could be elastic thermoplastic polymers or rubbers, in this case pre-impregnation or powder coating and pressing would be the fabrication process used. The samples would than undergo a series of characterization steps in order to characterize the matrix compatibility and performance. For the compatibly electron microscopy (HR-TEM, HR-SEM) and spectroscopy (SAXS, WAXS) will be used to examine the interface between the GNF and the matrix. From this kind of evaluation the adhesion of the matrix to the fiber as well as crystallinity and orientation of the matrix would be evident. In parallel the basic mechanical properties: UTS, elastic modulus, loss and storage modulus, elongation, stiffness and toughness, will be defined. From these characterization methods the compatibility and the synergetic effect of the matrix with the GNF will be decided and the most suitable matrix will be chosen for the rest of the project. For the selected composite material additional tests will be performed. It should be noted that for each proposed characterization method, different sample preparation and even different sample composition is needed. 
         [0112]    Predictable properties of GNF composite materials can be effective for future armor applications. It is well known that the mechanical behavior of a composite material is a function of its building material as well as its structure, trough this it can be tailor designed for specific service purposes. Characterization of armor-oriented materials requires dynamic load evaluation in wide range of impact loading rates. facility is equipped with a Hopkinson High Pressure Split Bar (HSPB) apparatus which allows Dynamic compression, tension, bending and shear testing in the range of 102-104 sec−1 strain rates. The output data is usually translated to a stress strain curve at various rates of dynamic loadings. This provides understanding whether the composite material possess a tendency to be affected by the strain rate i.e. it is a strain rate sensitive material. In this case, its strength is linked to the loading conditions, and, if it so, the parameters of constitutive equation will be obtained from these experiments. Correct constitutive equation will be referred by computerized simulative modeling with LS-Dyna tools as explained in section B.4.5 of this proposal. Structure/properties optimization will be carried out by iterations steps in cycles of structure modification versus properties enhancement. Analysis of composite and polymeric containing materials already has a certain level of developed theoretical and experimental base which will used at starting points of presented research proposal. 
         [0113]    The technique of planar impact experiment, which can supply data corresponding to dynamic strength at compression dynamic tests, such as Hugoniot Elastic Limit (HEL) at the strain rate range higher than 104 sec−1 and typically up to 107 sec−1. 
         [0114]    Characterization of composite materials under dynamic loading will be aimed on understanding of structure-properties relationships and service-aided design of the GNF composite material. Ballistic effectiveness of these materials will be evaluated then directly by means of ballistic evaluation, however optimization of the properties of composite materials will be based on comprehensive material analysis and understanding of its behavior under wide spectrum of loadings. 
         [0115]    Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.