Ceramic armour systems with a front spall layer and a shock absorbing layer

[0001] This application is entitled to the benefit of and claims priority from U.S. patent application No. 60/307,378, filed on Jul. 25, 2001, the entirety of which is incorporated herein by reference.

[0002] The present invention relates generally to the field of armours, especially hard armours. More particularly, the present invention relates to ceramic components, to ceramic component systems, and ceramic armour systems.

[0003] One of the ways of protecting an object from a projectile is equipping that object with an armour. These armours vary in shape and size to fit the object to be protected. A number of materials e.g., metals, synthetic fibres, and ceramics have been used in constructing the armours. The use of ceramics in constructing armours has gained popularity because of some useful properties of ceramics. Ceramics are inorganic compounds with a crystalline or glassy structure. While being rigid, ceramics are low in weight in comparison with steel; are resistant to heat, abrasion, and compression; and have high chemical stability. Two most common shapes in which ceramics have been used in making armours are as pellets/beads and plates/tiles, each having its own advantages and disadvantages.

[0004] U.S. Pat. No. 6,203,908 granted to Cohen discloses an armour panel having an outer layer of steel, a layer of plurality of high density ceramic bodies bonded together, and an inner layer of high-strength anti-ballistic fibres e.g., KEVLAR™.

[0005] U.S. Pat. No. 5,847,308 granted to Singh et al. discloses a passive roof armour system comprising of a stack of ceramic tiles and glass layers.

[0006] The U.S. Pat. No. 6,135,006 granted to Strasser et al. discloses a multi-layer composite armour with alternating hard and ductile layers formed of fibre-reinforced ceramic matrix composite.

[0007] Presently, there are two widely used designs of ceramic components in making armours. The first design, known as the MEXAS design in the prior art comprises a plurality of square planar ceramic tiles. The tiles have a typical size of 1″×1″, 2″×2″, or 4″×4″. The second design known as the LIBA design in the prior art comprises a plurality of ceramic pellets in a rubber matrix. Both designs are aimed at defeating a projectile. These designs protect an object from a projectile impacting at a low angle. However, the thickness of the tiles in the MEXAS design has to be varied depending upon the level of threat and the angle of the impacting projectile. This increases the weight of the ceramic component and subsequently of the armour. These ceramic components are useful for protecting an object from a low level of threat only and are not suitable for protecting an object from projectiles posing a high level of threat, e.g., the threat posed by a Rocket Propelled Grenade (RPG). Furthermore, an armour assembled by joining a plurality of individual tiles is vulnerable to any level of threat at joints.

[0008] Therefore, there is a need for producing improved ceramic components, ceramic component systems, and ceramic armour systems that are not only capable of defeating the projectile but are also capable of deflecting the projectile upon impact. There is also a need for reducing the weight of the ceramic components used in the armour systems. There is also a need for improved armour systems capable of deflecting and defeating projectiles posing various levels of threats. There is also a need for providing deflecting and defeating capabilities at the joint points of ceramic components. There is also a need for improved close multi-hit capability, reduced damaged area including little or no radial cracking, reduced back face deformation, and reduced shock and trauma to the object. There is also a need for reducing detection of infrared signature of an object. There is also a need for scattering radar signals by the object.

[0009] One object of the present invention to obviate or mitigate at least one of the above-recited disadvantages of previous ceramic components, ceramic component systems, and ceramic armour systems.

[0010] It is another object of the present invention to provide ceramic armour systems having improved ballistic performance and survivability, multi-hit capability, reduced damaged area, low areal density, flexible design, reduced back face deformation, shock, and trauma, and many stealth features over prior art systems for personnel protection or vehicle protection.

[0011] It is yet another object of the present invention to provide a ceramic armour system for vehicles, crafts, and buildings to protect the surfaces of these structures from damage by fragments.

[0012] It is yet another object of the present invention to provide a ceramic armour system that can be used as add-on armour without the requirement of an internal liner in the vehicle.

[0013] It is yet another object of the present invention to provide stealth features e.g., air gap, foam layer, and camouflage paint to minimize the attack in a ceramic armour system.

[0014] It is yet another object of the present invention to provide an improved ceramic component and improved ceramic component system that are capable of deflecting and defeating the projectile.

[0015] A related object of the present invention is to provide means of reducing weight of the ceramic components without compromising deflecting and defeating capabilities thereof.

[0016] Another object of the present invention is to provide ceramic armour systems that are capable of deflecting and defeating the projectiles posing various levels of threats.

[0017] The present invention provides a ceramic armour system having, in front to back order, an integral ceramic plate, or a plurality of interconnected ceramic components providing an integral plate, the ceramic plate having a deflecting front surface or a flat front surface, and a rear surface; a front spall layer bonded to the front surface of the ceramic plate; a shock-absorbing layer bonded to the rear surface of ceramic plate; and a backing which is bonded to the exposed face of the shock-absorbing layer.

[0018] The present invention also provides a ceramic armour system for vehicles comprising an assembly of an integral ceramic plate, or a plurality of interconnected ceramic components providing an integral plate, the ceramic plate having a deflecting front surface or a flat front surface, and a rear surface; a front spall layer bonded to the front surface of the ceramic plate; a shock-absorbing layer bonded to the rear surface of ceramic plate; wherein the assembly is bolted to the hull of a vehicle at a predetermined distance from the hull, thereby leaving an air gap between the shock-absorbing layer and the hull of the vehicle in order to reduce infrared signature of the vehicle.

[0019] The ceramic armour system includes a ceramic plate having a plurality of individual abutted or lapped planar ceramic components having a deflecting front surface which is preferably provided with a pattern of multiple nodes thereon. The ceramic plate may be monolithic strike plate, body armour, or protective shield, having a deflecting front surface which is preferably provided with a pattern of multiple nodes thereon. The ceramic plate may be a plurality of individual abutted or lapped curved ceramic components having a deflecting front surface which is preferably provided with a pattern of multiple nodes thereon.

[0020] The configuration of nodes in the ceramic components may be spherical, cylindrical, and conical. The nodes may be of the same size, thereby providing a mono-size distribution. The nodes may be of different sizes, thereby providing a bi-modal distribution. One or more of nodes may include longitudinal channel therethrough, thereby lowering the areal density of said armour. Partial nodes may be provided on the edges of each ceramic component for protecting an object from a threat at the joint points of ceramic components. The partial nodes at the edges of two ceramic components become full nodes when the ceramic components are aligned and joined by an adhesive.

[0021] In the ceramic armour system, edges of the ceramic components may be overlapping, bevelled, or parallel.

[0022] The ceramic component system may have a plurality of individual abutted or lapped planar ceramic components, each having a deflecting front surface which is preferably provided with a single node thereon in a polymer matrix. The shape of the ceramic components may be rectangular, triangular, hexagonal, or square.

[0023] The front spall may be a synthetic plastic sheath, a thermoplastic sheath, or a polycarbonate sheath. The front spall may be bonded to the ceramic component system by way of a polymer adhesive. The plastic adhesive may be a polyurethane adhesive.

[0024] The shock-absorbing layer may be at least one of a polymer-fibre composite, an aramid fibre, a carbon fibre, a glass fibre, a ceramic fibre, a polyethylene fibre, a ZYALON™ fibre a Nylon 66 fibre, or any combination thereof. The shock-absorbing fibre layer is bonded to rear surface of the ceramic plate, preferably by means of a polyurethane adhesive.

[0025] The backing may be at least one layer of poly-paraphenylene terephthalamide fibres (KEVLAR™), polyethylene fibres (SPECTRA™), glass fibres (DAYNEEMA™), ZYALON™ fibres, TITAN ZYALON™ fibres, TITAN KEVLAR™ fibres, TITAN SPECTRA™ fibres, TWARON™ fibres, and SPECTRA-SHIELD™ fibres or combinations thereof, or metals, e.g., steel or aluminum. The backing is bonded to the exposed face of said shock-absorbing layers preferably by a polyurethane adhesive.

[0026] The ceramic armour system may include at least two further support layers, e.g., ceramic components which may include, or may be devoid of nodes, or polymer-ceramic fibre composite components, or plastic components, or combination thereof. The support layers are bonded to each other and to the ceramic plate by an adhesive. The adhesive may be polyurethane or ceramic cement. The at least two further support layers are provided with an inter-layer of polymer-ceramic fibres therebetween. The interlayer is bonded to the support layers by an adhesive. The adhesive is preferably polyurethane.

[0027] The ceramic armour system may include at least one layer of commercially available foam (FRAGLIGHT™) for scattering radar signals.

[0028] The front spall of the ceramic armour system may be provided with a camouflage surface for minimizing attack.

[0029] The ceramic armour system may have a ceramic plate comprises a sandwich including a first layer of CERAMOR™ V, a first layer of CERAMOR™ L bonded to said first layer of CERAMOR™ V, a second layer of CERAMOR™ V bonded to said first layer of CERAMOR™ L, and a second layer of CERAMOR™ L bonded to said second layer of CERAMOR™ V.

[0048] The present invention provides improved ceramic components for use in ceramic armour systems embodying ceramic components for deflecting and defeating projectiles imposing various levels of threats. The present invention also provides a shock absorbing layer for reducing shock and trauma and for providing support to the armour. The present invention also provides enhanced stealth features. A number of terms used herein are defined below.

[0049] Ceramic means simple ceramics or ceramic composite materials. As used herein, the term “ceramic” is meant to embrace a class of inorganic, non-metallic solids that are subjected to high temperatures in manufacture or use, and may include oxides, carbides, nitrides, suicides, borides, phosphides, sulphides, tellurides, and selenides.

[0050] Deflecting means changing of direction of an incoming projectile upon impact.

[0051] Defeating means shattering of an incoming projectile upon impact.

[0052] Threat means an article or action having the potential to harm an object. In this disclosure, a projectile has been considered as a threat. However, the threat may come from any other article, for example, an army knife.

[0053] Ceramic component system and integral ceramic plate have been used synonymously in this disclosure.

[0054] Description of FIG. 1

[0055] FIG. 1 shows the cross section of one embodiment of personnel protection ceramic armour system 110 of the present invention. The ceramic armour system comprises a ceramic component 1110, 1210, or 1310 (to be described later). The ceramic component is an integral ceramic plate, or a plurality of interconnected ceramic components providing an integral plate (as will be further described with respect to FIG. 11). The ceramic plate 1110, 1210, or 1310 may have a flat front surface, or may have a deflecting front surface having at least one node thereon, and has a rear surface. A front spall layer 112 (to be described later) is bonded to the front surface of the ceramic component 1110, 1210, or 1310. A shock-absorbing layer 114 is bonded to the rear surface of ceramic component 1110, 1210, or 1310. The shock-absorbing layer 114 may be formed of polymer-fibre composites including aramid fibres, carbon fibres, glass fibres, ceramic fibres, polyethylene fibres, ZYALON™, Nylon 66, or a combination thereof. The shock-absorbing layer 114 may be obtained by layering one type of fibre over another fibre in a suitable orientation and bonding them together with an adhesive. In a preferred embodiment, a shock-absorbing layer of 2 to 8 layers may be created by gluing, either with an epoxy glue or with a polyurethane glue, one layer of carbon fibre over a layer of aramid and repeating the process as often as necessary. The orientation of the fibre layers may be parallel or at any other angle to one another. The shock-absorbing layer 114 may be glued to a polycarbonate sheath at the back face. Use of a shock-absorbing layer 114 in a ceramic armour system reduces shock and trauma, and provides support. This advantage of the shock-absorbing layer 114 has never been disclosed or suggested before in the prior art. A backing 116 (to be described later) is bonded to the exposed face of the shock-absorbing layer 114. These layers are bonded together, preferably with an adhesive.

[0056] In another embodiment (not shown), the shock-absorbing layer is used in combination with a ceramic mosaic component system in a chest plate configuration for reducing shock and trauma, and providing support, together with the front spall and the backing. The ceramic mosaic is a known ceramic configuration that is economical because ceramic tiles are mass-produced by pressing.

[0057] In yet another embodiment (not shown), the shock-absorbing layer is used with a flat ceramic base, together with the front spall and the backing, for reducing shock and trauma, and providing support.

[0058] Description of FIG. 2

[0059] The ceramic armour system of the present invention can also protect vehicles, crafts and buildings.

[0060] FIG. 2 shows a cross-section of one embodiment of such a ceramic armour system 210 which comprises a ceramic component 1110, 1210, 1310, or 1724 (to be described later). The ceramic component is an integral ceramic plate, or a plurality of interconnected ceramic components providing an integral plate (as will be further described with respect to FIG. 11). The ceramic component 1110, 1210, 1310, or 1724 may have a deflecting front surface including at least one node thereon or may have a flat front surface, and a rear surface. A front spall layer 212 (to be described later) is bonded to the front surface of the ceramic component 1110, 1210, 1310, or 1724. A shock-absorbing layer 214 (to be described later) is bonded to the rear surface of ceramic plate 1110, 1210, or 1310. The above-described sub-structure 215 is disposed at a predetermined distance from the exposed face of the hull 218 of the vehicle with bolts 217. The hull 218 of the vehicle may include a liner 220. This provides an air gap 216 between the exposed face of the shock-absorbing layer 214 and the hull 218. The air-gap 216 between the hull 218 of the vehicle and the shock-absorbing layer 214 of the armour is provided to reduce infrared signature of the vehicle. In a preferred embodiment, the air-gap is 4 to 6 mm. The above-described sub-structure 215 can also be bolted directly to the bull without the air gap if so needed. With the armour system of the present invention, no liner 220 inside the vehicle is required, although it is optional, like the one needed with the prior art MEXAS system.

[0061] Scattering of the radar signals is normally obtained by adding a commercially-available foam e.g., FRAGLIGHT™ on top of the front spall layer of the armour system 210. However, together with the nodes on the ceramic component, the scattering of the radar signals can be enhanced significantly.

[0062] In one embodiment (not shown), one layer of foam in conjunction with noded ceramic armour systems of the present invention was used to scatter as much as 80% of the incoming signal. In a preferred embodiment, the layer of foam is 4 mm thick.

[0063] In another embodiment (not shown), the MAP ceramic component system (to be described later) can be used in the ceramic armour system of this invention that is distinct and superior to the presently-used MEXAS and LIBA systems, to protect vehicles, crafts and buildings. The ceramic material, shape, size, and thickness of the ceramic armour system is determined by the overall design of the ballistic system, the level of threat, and economics. The remaining features, as specified above, may be added to create ceramic armour system for vehicles, crafts and buildings.

[0064] In yet another embodiment (not shown), the front spall layer 212 of the armour is provided with a camouflage to minimize an attack.

[0065] Description of FIG. 3 and FIG. 4

[0066] FIG. 3 and FIG. 4 show a ceramic component 310 having a square ceramic base 312 with a plurality of spherical nodes 314 of one size disposed thereon. While FIG. 3 shows the shape of the ceramic base 312 to be square, it can alternatively be rectangular, triangular, pentagonal, hexagonal, etc. The ceramic component 310 is shown to be planar herein, but it can alternatively be curved. The ceramic component 310 may have overlapping complementary “L”-shaped edges or 45° bevelled edges or 90° parallel edges for abutting the ceramic components to form a ceramic component system to be described hereafter in FIG. 11. The size and shape of the ceramic component 310 may also be varied depending upon the size of the object to be protected.

[0067] In other embodiments (not shown), the shape, size, distribution pattern, and density of distribution of the nodes may be varied by those skilled in the art to achieve improved deflecting and defeating capabilities. The nodes may be spherical, conical, cylindrical, or a combination of thereof The nodes may be small or large. If nodes of the same size are provided on the ceramic base, then the distribution is called “mono-size distribution.” If nodes of different sizes are provided on the ceramic base, then the distribution is called “bi-modal distribution.” The nodes may be distributed in a regular or random pattern. The nodes may be distributed in low or high density. Furthermore, half nodes are provided on the edges of each ceramic component base. The half nodes at the edges of two ceramic components, for example, become one when the ceramic bases are aligned and joined by an adhesive. Such arrangement of nodes at the edges protects an object from a threat at the joint points of ceramic components.

[0068] Description of FIG. 5 and FIG. 6

[0069] FIG. 5 and FIG. 6 show a ceramic component 510 having a square ceramic base 512 regular pattern of high density. While FIG. 5 shows the shape of the ceramic base 512 to be square, it can alternatively be rectangular, triangular, pentagonal, hexagonal, etc. The ceramic component 510 is shown to be planar, but it can alternatively be curved. The ceramic component 510 may have overlapping complementary “L”-shaped edges or 45° bevelled edges or 90° parallel edges for abutting the ceramic components to form a ceramic component system to be described hereafter in FIG. 11. The size and shape of the ceramic component 510 may also be varied depending upon the size of the object to be protected.

[0070] Description of FIG. 7 and FIG. 8

[0071] In another embodiment, to reduce the weight of the ceramic component, a longitudinal channel is provided through each node and the ceramic base portion underneath each node. FIG. 7 and FIG. 8 show a ceramic component 710 having a square ceramic base 712 with spherical nodes 714 of one size thereon provided with longitudinal channels 716 therethrough. Not all nodes and the ceramic base underneath nodes may be provided with the channels. The provision of the longitudinal channels 716 reduces the weight of the ceramic component by up to 15% while maintaining the improved deflecting and defeating capabilities. While FIG. 7 shows the shape of the ceramic base 712 to be square, it can alternatively be rectangular, triangular, pentagonal, hexagonal, etc. The ceramic component 712 is shown to be planar, but it can alternatively be curved. The ceramic component 712 may have overlapping complementary “L”-shaped edges or 45° bevelled edges or 90° parallel edges for abutting the ceramic components to form a ceramic component system to be described hereafter in FIG. 11. The size and shape of the ceramic component 712 may also be varied depending upon the size of the object to be protected.

[0072] Description of FIG. 9 and FIG. 10

[0073] FIG. 9 and FIG. 10 show a ceramic component 910 having a square ceramic base 912 with spherical nodes of two different sizes 914, 916 thereon which are each provided with a longitudinal channel 918 therethrough. Not all nodes and the ceramic base underneath the nodes may be provided with the channels. While FIG. 9 shows the shape of the ceramic base 710 to be square, it can alternatively be rectangular, triangular, pentagonal, hexagonal, etc. The ceramic component 910 is shown to be planar, but it can alternatively be curved. The ceramic component 910 may have overlapping complementary “L”-shaped edges or 45° bevelled edges or 90° parallel edges for abutting the ceramic components to form a ceramic component system to be described hereafter in FIG. 11. The size and shape of the ceramic component 910 may also be varied depending upon the size of the object to be protected.

[0074] Description of FIG. 11

[0075] In still another embodiment, the ceramic components described above may be joined to form a ceramic component system. FIG. 11 shows a cross section of three embodiments of a ceramic component system 1110 formed by abutting a plurality of ceramic components which are described above in FIG. 3 to FIG. 10 and more especially the ceramic components shown in FIG. 9. Such a system is designated as Monolithic Advance Protection (MAP). The ceramic component is provided with, for example, “L”-shaped edges 1114, 1116 on each side of the component. Two adjacent ceramic components may be joined by aligning the “L”-shaped edges 114, 116 and by filling the gap with an adhesive, preferably polyurethane and/or polyurethane thermoplastic. The edges of the ceramic component may also be cut to provide 45° bevels 1112 to facilitate aligning. The bevelled edges of 45° provide flexibility to the ceramic component system or to the ceramic armour system where a plurality of components is used in assembling such systems. The edges of the ceramic component may be cut at 90° to provide edges 1113 to facilitate aligning.

[0076] Description of FIG. 12

[0077] A still further embodiment is shown in FIG. 12 which shows a portion of the top plan view of another ceramic component systems that may be formed by embedding a plurality of ceramic components described above in FIG. 2 to FIG. 10 in a polymer adhesive matrix. Such a system is designated as CELLULAR ADVANCE PROTECTION (CAP). In the embodiment shown in FIG. 12, the CAP system 1210 comprises a plurality of ceramic components, each having a hexagonal ceramic base 1212 with one spherical node 1214 provided with a channel 1216 therethrough, that are joined together in a flat layer by an adhesive 1218, preferably polyurethane. In the case of CAP, smaller hexagonal ceramic components with one or few nodes are used. The layer of hexagonal ceramic components makes use of the space efficiently and creates a flexible ceramic system suitable for incorporation in armours for objects with contours, e.g., body parts.

[0078] Description of FIG. 13

[0079] An embodiment of a multi-layer ceramic component system is shown in FIG. 13 which shows a cross section of a LAYERED ADVANCE PROTECTION (LAP) system 1310 for protecting an object from a high level of threat. The LAP system comprises at least one layer of the MONOLITHIC ADVANCE PROTECTION (MAP) system 1110 described above and at least two support layer 1311, 1312, which may be formed of ceramic components which are devoid of nodes, or polymer-ceramic fibre composite components, or plastic components, or a combination thereof. The MAP system 1110 and the first support layer 1311 are bonded together by an adhesive. The adhesive may be polyurethane or ceramic cement. The second support layer 1312 is bonded to the first support layer 1311 and to the rear spall layer. In the embodiment shown in FIG. 13, the first and second support layers 1311, 1312 are formed of different ceramic components devoid of nodes which are prepared from the ceramic material CERAMOR™ or ALCERAM-T™. The CERAMOR™ is used for providing a mechanical function and ALCERAM-T™ is used for providing a thermo-mechanical function. The two support layers 1311, 1312 may be provided with an inter-layer 1314 of a polymer-ceramic fibre therebetween. The two layers 1311, 1312 and the inter-layer 1314 are bonded by an adhesive, preferably polyurethane. The two support layers 1311, 1312 may be duplicated as many times as desired depending upon the level of protection required.

[0080] Description of FIG. 14 and FIG. 15

[0081] The MAP, CAP, and LAP ceramic component systems described above may be used to make an improved personnel ceramic armour system. FIG. 14 and FIG. 15 show an embodiment of an improved personnel ceramic armour system 1410. This system comprises, in front to back order, at least one layer each of a front spall layer 1412, the ceramic component system, including MAP 1110, CAP 1210, or LAP 1310, a rear spall layer 1414, and a backing 1416. These layers are bonded together, preferably with an adhesive.

[0082] The front spall layer 1412 is a plastic sheath and is bonded to the front of the ceramic component system 1110, 1210, or 1310 by way of a polymer adhesive which is disposed between the nodes. The polymer adhesive is a thermoplastic, preferably a polyurethane adhesive and/or a polyurethane thermoplastic film.

[0083] The rear spall layer 1414 is also a plastic sheath and is bonded to the back of the ceramic component system 1110, 1210, or 1310 by a polymer adhesive, preferably polyurethane. The plastic sheath used in front spall layer 1412 and rear spall layer 1414 may be formed from a polycarbonate sheath. The polymer adhesive which is used to bond the rear spall layer 1414 to the ceramic component system 1110, 1210, or 1310 may be a polyurethane adhesive and/or a polyurethane thermoplastic. The spall layers i.e., the front spall layer 1412 and the rear spall layer 1414 are provided to improve multi-hit capability of the armour.

[0084] The backing 1416 is at least one layer of poly-paraphenylene terephthalamide fibres, polyethylene, glass fibres, or a metal, wherein the metal may be steel, aluminium, or any other suitable metal. The poly-paraphenylene terephthalamide fibres, polyethylene, glass fibres are known by trade names of KEVLAR™, SPECTRA™, and DAYNEEMA™, respectively.

[0085] Alternatively, the backing 136 could be made from a combination of fibres of KEVLAR™, SPECTRA™, and DAYNEEMA™, ZYALON™, TITAN ZYALON™, TITAN KEVLAR™, TITAN SPECTRAM™, TWARON™, and SPECTRA-SHIELD™ to reduce cost and to obtain the same performance. Such backing is designated herein as “degraded backing.” With the ceramic armour system of the present invention, the backing is required to capture fragments of the projectile only since the ceramic component system and shock-absorbing layer (described hereabove) stops the projectile before the projectile reaches the backing.

[0086] An interlayer 1418 may be disposed in-between the rear spall layer 1414 and the backing 1416 in order to reduce back face deformation. The inter-layer 1418 may be formed of a polymer-ceramic fibre composite.

[0087] Description of FIG. 16

[0088] FIG. 16 shows one embodiment of an improved personnel ceramic armour system 1610 which includes, in front to back order, one layer of a polycarbonate front spall layer 1612, one layer of the ceramic component system MAP 1110 (as described hereabove), a shock-absorbing composite layer 1614 made of 2 to 8 layers of glass fibres or aramid fibres, carbon fibres, and polycarbonate, glass fibres, or carbon fibres, wherein each layer is disposed at a suitable angle e.g, 90° to the previous layer, and a degraded backing 1616. These layers are bonded together, preferably, with a polymer adhesive. The polymer adhesive is a thermoplastic, preferably a polyurethane adhesive and/or a polyurethane thermoplastic film. Instead of using an adhesive, the front spall, the shock-absorbing composite layer, and the degraded backing may be adhesive-impregnated, and thus may be used to manufacture the armour system.

[0089] In manufacturing, the personnel armour system is assembled as a sandwich by coating the adhesive on the rear side of the ceramic plate, then over laying the shock-absorbing layer or layers thereon, coating the rear side of the shock-absorbing layer or layers with an adhesive, over layering the backing over the adhesive, coating the front of the ceramic plate with the adhesive and over laying the front spall layer. All of the assembled layers are then held together with a plurality of clamps and placed in an with spherical nodes of two different sizes 514, 516 thereon which are distributed in a autoclave under controlled temperature and pressure for integration.

[0090] Description of FIG. 17

[0091] FIG. 17 shown an embodiment of a LAP system for protection of vehicles from a high level threat posed by, for example, an RPG or shape charge. The ceramic component system is prepared by alternating layers of two different types of ceramics having different properties. For example, a layer of CERAMOR™ V which has high thermal property is alternated with a layer of CERAMOR™ L having a high ballistic property.

[0092] FIG. 17 shows a side view of an embodiment of an armour system 1710 utilizing a LAP system 1724 comprising in front to back order, a front spall layer 1712, a first layer of CERAMOR™ V 1714, a first layer of CERAMOR™ L 1716, a second layer of CERAMOR™ V 1718, a second layer of CERAMOR™ L 1720, and a shock-absorbing layer 1722. The complete assembly can then be bolted onto a vehicle for protection, preferably with an air gap or alternatively without an air gap. Such armour systems showed improved ballistic performance in tests done by Department of National Defence in Canada.

[0093] CERAMOR™ ceramic composite used in the present invention is a tough ceramic composite material that provides close multi-hit capability.

[0094] The personnel donning the armour are often subjected to multiple hits over time. Thus, from time to time it is essential to determine if the future protective capabilities of an armour have been compromised by past attacks. That is, it would be essential to determine stress level of a personnel armour system. The “stress level” herein means cracks appearing in the ceramic plate due to the number of hits taken by the armour. Normally, stress level of an armour system is determined by X-ray technique, which method is quite expensive.

[0095] In an embodiment, a cover of a pressure sensitive film (e.g., FUJI Film™) is provided over the front spall layer for determining stress level of a personnel armour system. Initially the film is transparent but depending upon the number of hits the armour takes, the film develops colour spots corresponding to pressure points generated by hits. These colour spots can then be used to determine the life of the armour and if the armour is still suitable to wear.

[0096] When a plurality of individual ceramic components are used in making a ceramic armour system, individual ceramic components are aligned sideways by abutting “L”-shaped, 45° bevelled, or 90° parallel edges. The layer of ceramic components thus formed is overlaid with an adhesive, preferably polyurethane, between nodes to prepare a flat surface, followed by a layer of {fraction (1/16)} or {fraction (1/32)} inches of polyurethane thermoplastic sheet. The front spall layer made of polycarbonate or laminated plastic is then laid over the ceramic components and adhesives as shown in FIGS. 15 and 16. The entire assembly of various layers is then subjected to a high pressure and temperature regime to bond ceramic components and various layers in the assembly. The rear spall layer and the backing may be bonded to assembled layers at the same time or they may be assembled in a group first and then the group is bonded to the assembled layers. Different layers may be bonded together in one group or in different groups. The different groups may then be bonded together to form one group. Epoxy resins may be used as an adhesive.

[0097] The improved deflecting and defeating capability of the ceramic components, ceramic component systems, and ceramic armour systems described herein was confirmed by conducting depth penetration tests. An armour is considered improved if it showed reduced depth of penetration or no penetration in comparison with penetration which was allowed by the prior art. As an example, the personnel ceramic armour system was subjected to depth penetration tests. In comparison to the prior art, ceramic components devoid of nodes, the personnel ceramic armour system shows reduced depth of penetration or no penetration.

[0098] A ceramic component devoid of nodes can only protect an object from the threat of a level IV armour-piercing projectile having a diameter of 7.62 mm. In comparison, the use of a single layer of a MAP ceramic component system can deflect and defeat a threat posed by a level V armour-piercing projectile having a diameter of 12.5 mm.

[0099] Often objects are subjected to higher levels of threats. Presently, only active armours are employed to protect objects, for example, tanks from high level threats. A Rocket Propelled Grenade (RPG) usually poses such a threat. The active armours generally include explosives that are provided on vulnerable areas of the object to be protected to counter-attack the approaching RPG. The active armours, though effective, can accidentally explode onto the surface of the object to be protected, thereby endangering the object and/or the life of the personnel inside the object. Generally, the RPG ejects molten Cu (Cu plasma jet) at a very high temperature and pressure onto the surface of the object after the impact. The Cu plasma jet pierces through the walls of the object and provides an avenue for the entry of bomblets into the object. Once inside the object, the bomblets explode, destroying the object and the personnel inside the object. The Cu plasma jet can pierce through 0.8 to 1.0 m of steel or 5 feet of concrete.

[0100] A multi-layer ceramic component system disclosed herein has been shown to deflect and defeat the high level of threat posed by the Cu plasma jet of the RPG. In addition to MAP on the top, one such system provides two supporting layers underneath the MAP. The two supporting layers made from two types of ceramic material, each having different high melting temperature resisting-properties and pressure-resisting properties. These support layers protect the object from the Cu plasma jet of the RPG in a stepwise manner. For example, first support layer which is made of CERAMOR™ which has a melting temperature of 2500° C. provides the first level of resistance to the high temperature and pressure of the Cu plasma jet of the RPG. The first layer absorbs most of the temperature and a part of the pressure from the Cu plasma jet of the RPG, but the first support layer eventually cracks. The second support layer which is made of ALCERAM-T™ which has a melting temperature of 3000° C. provides the second level of resistance to the high temperature and pressure of the Cu plasma jet of the RPG. The second layer absorbs the remaining temperature and pressure of the Cu plasma jet of the RPG, and does not melt or crack. Even if the second layer melts or crack, when the heat will have dissipated, the second support layer will solidify again to provide protection. Thus, by providing two support layers of different ceramic materials, the present invention protects against the high temperature and pressure generated by the Cu plasma jet of the RPG. The two support layers may also dissipate the temperature radially. The two support layers may be provided with an interlayer of polymer-ceramic fibres therebetween to provide more resistance to the temperature effect of the Cu plasma jet of the RPG.

[0101] The ceramic armour systems of the present invention passed the most stringent international testing. All CERAMOR™ systems were extensively tested for National Institute of Justice level III and IV threats. The testing of armour samples was conducted by H P White Laboratory (3114, Scarboro Road Street, Maryland 21154-1822, USA). A variety of ammunition was used during testing.

[0102] The test samples for the personnel protection armour system were mounted on an indoor range 50 feet from the muzzle of a test barrel to produce zero degree obliquity impacts. Photoelectric lumiline screens were positioned at 6.5 and 9.5 feet which, in conjunction with elapsed time counter (chronographs), were used to compute projectile velocities 8.0 feet forward of the muzzle. Penetrations were determined by visual examination of a witness panel of 0.020 inch thickness of 2024T3 aluminum positioned 6.0 inches behind and parallel to the test samples.

[0103] It was found that a CERAMOR™ MAP strike plate of 2.6 kg could stop two 7.62 mm AP M2 projectiles at a velocity of 875 m/s or two 7.62 AP Swiss projectiles with tungsten carbide core at 825 m/s.

[0104] A CERAMOR™ MAP strike plate armour system having 3.5 lbs/sq.ft. of ceramic weight and total weight of 5.65 lbs/sq.ft. with SPECTRA™ backing was tested for level III+ test which has a requirement of stopping two bullets out of four bullets. The CERAMOR™ MAP strike plate test armour stopped the all four bullets.

[0105] A CERAMOR™ MAP strike plate armour system having 4.5 lbs/sq.ft. of ceramic and total weight of 6.5 lbs/sq.ft. was tested for level IV+ test which has a requirement of stopping one 7.62 mm AP Ml bullet. This CERAMOR™ MAP strike plate armour system stopped two 7.62 mm AP M1 bullets.

[0106] The test samples for the vehicle protection armour system were mounted on an indoor range of 45 feet from the muzzle of a test barrel to produce zero degree obliquity impacts. Photoelectric lumiline screens were positioned at 15.0 and 35.0 feet which, in conjunction with elapsed time counter (chronographs), were used to compute projectile velocities 25 feet forward of the muzzle. Penetrations were determined by visual examination of a witness panel of 0.020 inch thickness of 2024T3 aluminum positioned 6.0 inches behind and parallel to the test samples.

[0107] The test armour plate of the present invention having a size of 12″×12″ was hit by 5 projectiles (14.5 mm AP B32) at 900 m/s at less than 2″ apart. No penetration was observed.

[0108] The effectiveness of a ceramic component, and of an armour using such ceramic components, in protecting an object from the impact of projectile is improved by providing nodes on the front surface of the ceramic base. The provision of nodes adds the deflecting capability to the ceramic component and to the armour using ceramic components. The nodes change the angle of the impacted projectile and retard the passage of the projectile through the ceramic component. The projectile is then easily defeated. The presence of nodes on the ceramic component disclosed in the present invention is more effective in protecting an object than a ceramic component devoid of nodes, thereby eliminating the need for using thicker ceramic components for protecting an object from the same level of threat. The reduced thickness leads to a lighter ceramic component, ceramic component system, and ceramic armour system. The provision of channels also adds to the lightness of ceramic components and ceramic armour systems. The stealth features, e.g., air gap, foam layer, and camouflage surface minimizes the attack.

[0109] Thus, the ceramic armour systems of the present invention provide improved ballistic performance and survivability, multi-hit capability, reduced damaged area, low areal density, flexible design, reduced back face deformation, shock, and trauma, and many stealth features over prior art systems. The ceramic armour system for vehicles, crafts, and buildings in addition also protects the surfaces of these structures from damage by fragments. For example, in the case of a vehicle, it protects the hull. The ceramic armour systems for vehicles, for example, tanks, can also be used as an add-on armour without the requirement of an internal liner.

[0110] The armour system described herein functions to protect an object by deflecting and defeating a projectile. The ceramic armour system provides better protection from projectile threats to ground vehicles, aircrafts, watercrafts, spacecrafts, buildings, shelters, and personnel, including body, helmet and shields.

[0111] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. Consequently, such changes and modifications are properly, equitably, and “intended” to be, within the full range of equivalence of the following claims.