Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
  • F41H5/00—Armour; Armour plates
  • F41H5/02—Plate construction
  • F41H5/04—Plate construction composed of more than one layer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
  • F41H5/00—Armour; Armour plates
  • F41H5/02—Plate construction
  • F41H5/04—Plate construction composed of more than one layer
  • F41H5/0414—Layered armour containing ceramic material
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
  • F41H5/00—Armour; Armour plates
  • F41H5/02—Plate construction
  • F41H5/04—Plate construction composed of more than one layer
  • F41H5/0492—Layered armour containing hard elements, e.g. plates, spheres, rods, separated from each other, the elements being connected to a further flexible layer or being embedded in a plastics or an elastomer matrix

Definitions

• the present invention relates to a composite armor panel. More particularly, the invention relates to an armored panel providing lightweight ballistic protection which may be worn by the user, as well providing ballistic protection for protecting light and heavy mobile equipment and vehicles against high-speed armor-piercing projectiles or fragments. The invention also includes methods for manufacturing the panel. Background Art
• the first consideration is weight.
• Protective armor for heavy but mobile military equipment such as tanks and large ships, is known.
• Such armor usually comprises a thick layer of alloy steel, which is intended to provide protection against heavy and explosive projectiles.
• reduction of weight of armor, even in heavy equipment is an advantage since it reduces the strain on all the components of the vehicle.
• such armor is quite unsuitable for light vehicles such as automobiles, jeeps, light boats, or aircraft, whose performance is compromised by steel panels having a thickness of more than a few millimeters, since each millimeter of steel adds a weight factor of 7.8 kg/m 2 .
• Armor for light vehicles is expected to prevent penetration of bullets of any type, even when impacting at a speed in the range of 700 to 1000 meters per second.
• a second consideration is cost. Overly complex armor arrangements, particularly those depending entirely on synthetic fibers, can be responsible for a notable proportion of the total vehicle cost, and can make its manufacture non- profitable.
• a third consideration in armor design is compactness.
• a thick armor panel including air spaces between its various layers, increases the target profile of the vehicle.
• a fourth consideration relates to ceramic plates used for personal and light vehicle armor, which plates have been found to be vulnerable to damage from mechanical impacts caused by rocks, falls, etc.
• Ceramic materials are nonmetallic, inorganic solids having a crystalline or glassy structure, and have many useful physical properties, including resistance to heat, abrasion and compression, high rigidity, low weight in comparison with steel, and outstanding chemical stabiity. Such properties have long drawn the attention of armor designers, and solid ceramic plates, in thicknesses ranging from 3 mm. for personal protection to 50 mm. for heavy military vehicles, are commercially available for such use.
• a common problem with prior art ceramic armor concerns damage inflicted on the armor structure by a first projectile, whether stopped or penetrating. Such damage weakens the armor panel, and so allows penetration of a following projectile, impacting within a few centimeters of the first. Disclosure of the Invention
• the present invention is therefore intended to obviate the disadvantages of prior art ceramic armor, and in a first embodiment to provide an armor panel which is effective against small-caliber fire-arm projectiles, yet is of light weight, i.e,
• an armor panel which is effective against a full range of armor-piercing projectiles from 5.56 mm and even up to 30 mm, as well as from normal small-caliber fire-arm projectiles, yet is of light weight, i.e, having a weight of less than 185 kg/m > even f° r tnt9 heavier armor provided by the present invention for dealing with 25 and 30 mm projectiles.
• a further object of the invention is to provide an armor panel which is particularly effective in arresting a plurality of armor-piercing projectiles impacting upon the same general area of the panel.
• a composite armor plate for absorbing and dissipating kinetic energy from high velocity, armor-piercing projectiles, said plate comprising a single internal layer of high density ceramic pellets which are directly bound and retained in plate form by a solidified material such that the pellets are bound in a plurality of adjacent rows, characterized in that the pellets have an Al 2 0 3 content of at least 93% and a specific gravity of at least
• the majority of the pellets each have at least one axis of at least 3 mm length 4 and are bound by said solidified material in a single internal layer of adjacent rows, wherein a majority of each of said pellets is in direct contact with at least 4 adjacent pellets, and said solidified material and said plate are elastic.
• a composite armor plate as defined above, wherein the majority of the pellets each have at least one axis in the range of about 6-19 mm, and are bound by said solidified material in a single internal layer of adjacent rows, wherein a majority of each of said pellets is in direct contact with at least 4 adjacent pellets, and the total
• a composite armor plate as defined above, wherein the majority of said pellets each have at least one axis having a length in the range of from about 20 to 40 mm and
• the weight of said plate does not exceed 185 kg/m .
• each of a majority of said pellets is in direct contact with at least six adjacent pellets.
• Said solidified material can be any suitable material which retains elasticity upon hardening at the thickness used, such as aluminum, epoxy, a thermoplastic polymer, or a thermoset plastic, thereby allowing curvature of the plate without cracking to match curved surfaces to be protected, including body surfaces, as well as elastic reaction of the plate to incoming projectiles to allow increased contact force between adjacent pellets at the point of impact.
• suitable material which retains elasticity upon hardening at the thickness used, such as aluminum, epoxy, a thermoplastic polymer, or a thermoset plastic, thereby allowing curvature of the plate without cracking to match curved surfaces to be protected, including body surfaces, as well as elastic reaction of the plate to incoming projectiles to allow increased contact force between adjacent pellets at the point of impact.
• the elasticity of the material used in preferred embodiments of the present invention serves, to a certain extent, to increase the probability that a projectile will simultaneously impact several pellets, thereby increasing the efficiency of the stopping power of the panel of the present invention. 5
• a multi- layered armor panel comprising an outer, impact-receiving panel of composite armor plate as hereinbefore defined, for deforming and shattering an impacting high velocity, armor-piercing projectile; and an inner layer adjacent to said outer panel, comprising a second panel of elastic material for absorbing the remaining kinetic energy from said fragments.
• Said elastic material will be chosen according to cost and weight considerations and can be made of any suitable material, such as aluminum or woven textile material.
• a multi-layered armor panel comprising an outer, impact-receiving panel of composite armor plate as hereinbefore defined, for deforming and shattering an impacting high velocity, armor-piercing projectile; and an inner layer adjacent to said outer panel, comprising a second panel of tough woven textile material for causing an asymmetric deformation of the remaining fragments of said projectile and for absorbing the remaining kinetic energy from said fragments, wherein said multi-layered panel is adapted to stop three projectiles fired sequentially at a triangular area of said multi-layered panel, wherein the height of said triangle is substantially equal to three times the axis of said pellets.
• composite armor plate comprising a mass of spherical ceramic balls distributed in an aluminum alloy matrix is known in the prior art.
• prior art composite armor plate suffers from one or more serious disadvantages, making it difficult to manufacture and less than entirely suitable for the purpose of defeating metal projectiles.
• the ceramic balls are coated with a binder material containing ceramic particles, the coating having a thickness of between 0.76 and 1.5 and being provided to help protect the ceramic cores from damage due to thermal shock when pouring the molten matrix material during manufacture of the plate.
• the coating serves to separate the harder ceramic cores of the balls from each other, and will act to dampen the moment of energy which is transffed and hence shared between the balls in response to an impact from a bullet or other projectile. Because of this and also because the material of the coating is inherently less hard than that of the ceramic cores, the stopping power of a plate constructed as described in said patent is not as good, weight for weight, as that of a plate in accordance with the present invention in which the hard ceramic pellets are in direct contact with adjacent pellets.
• U.S. Patent 3,705,558 discloses a lightweight armor plate comprising a layer of ceramic balls.
• the ceramic balls are in contact with each other and leave small gaps for entry of molten metal.
• the ceramic balls are encased in a stainless steel wire screen; and in another embodiment, the composite armor is manufactured by adhering nickel-coated alumina spheres to an aluminum alloy plate by means of a polysulfide adhesive.
• a composite armor plate as described in the McDougal, et al. patent is difficult to manufacture because the ceramic spheres may be damaged by thermal shock arising from molten metal contact. The ceramic spheres are also sometimes displaced during casting of molten metal into interstices between the spheres.
• Huet U.S. Patents 4,534,266 and 4,945,814 propose a network of interlinked metal shells to encase ceramic inserts during casting of molten metal. After the metal solidifies, the metal shells are incorporated into the composite armor. It has been determined, however, that such a network of interlinked metal shells substantially increases the overall weight of the armored panel and decreases the stopping power thereof.
• McDougal suggests and teaches an array of ceramic balls disposed in contacting pyrimidal relationship, which arrangement also substantially increases the overall weight of the armored panel and decreases the stopping power thereof, due to a billiard-like effect upon impact.
• the novel armor of the present invention traps incoming projectiles between several very hard ceramic pellets which are held in a single layer in rigid mutual abutting relationship.
• the relatively moderate size of the pellets ensures that the damage caused by a first projectile is localized and does not spread to adjoining areas, as in the case of ceramic pellets.
• a major advantage of the novel approach provided by the present invention is that it enables the fabrication of different panels adapted to deal with different challenges, wherein e.g. smaller pellets can be used for personal armor and for meeting the challenge of 5.56, 7.62 and 9 mm projectiles, while larger pellets can be used to deal with foreseen challenges presented by 14.5 mm, 25 mm and even 30 mm armor piercing projectiles.
• cylindrical pellets having a diameter of 9.5 mm and a height of between 9.5 and 11.6 mm, as well as cylindrical pellets having a diameter of 12.7 mm and a height of between 9.5 and 11.6 mm were more than adequate to deal with projectiles of between 5.56 and 9 mm, when arranged in a panel according to the present invention.
• cylindrical pellets having a diameter of 19 mm and a height of between 22 and 26 mm were more than adequate to deal with armor piercing 14.5 mm projectiles.
• An incoming projectile may contact the pellet array in one of three ways:
• the pellets used are either spheres or shapes approaching a spherical form or hexagonal in cross-section, and this form, when supported in a rigid matrix, has been found to be significantly better at resisting shattering than rectangular shapes.
• the present invention provides a method for producing a composite armor plate as defined hereinabove, comprising providing a mold having a bottom, 9 two major surfaces, two minor surfaces and an open top, wherein the distance between said two major surfaces is from about 1.1 to about 1.4 times the height of said pellets; inserting said pellets into said mold to form a plurality of superposed rows of pellets extending substantially along the entire distance between said minor side surfaces, and from said bottom substantially to said open top; incrementally heating said mold and the pellets contained therein to a temperature of at least 100°C above the flow point of the material to be poured in the mold; pouring molten material into said mold to fill the same; allowing said molten material to solidify; and removing said composite armor plate from said mold.
• the present invention also provides a method for producing a composite armor plate, comprising providing a mold having a bottom, two major surfaces, two minor surfaces and an open top, wherein the distance between said two major surfaces is from about 1.1 to 1.4 times the height of said pellets; inserting said pellets into said mold to form a plurality of superposed rows of pellets extending substantially along the entire distance between said minor side surfaces, and from said bottom substantially to said open top; pouring liquid epoxy resin into said mold to fill the same; allowing said epoxy to solidify; and removing said composite armor plate from said mold.
• said epoxy can be applied by spraying onto pellets arranged in a horizontal mould, instead of being poured, as known per se in the art.
• said pellets do not necessarily have to be completely covered on both sides by said solidified material, and they can touch or even bulge from the outer surfaces of the formed panel.
• Fig. 1 is a perspective, fragmented view of a preferred embodiment of an armor panel according to the invention
• Figs. 2 and 3 are perspective views of further pellet embodiments
• Fig. 4 is a sectional view of a two-layer embodiment of the armor panel
• Fig. 5 is a diagrammatic view of a mold used in the methods for manufacturing the panel
• Fig. 6 is a perspective view of a small section of a panel, wherein a castable material fills the voids between bodies
• Figs. 7a and 7b illustrate projectile impact arrays on panels according to the present invention. Description of Preferred Embodiments
• a panel 14 is formed from a solidified material 16, the panel having an internal layer of high-density ceramic pellets 18.
• the outer faces of the panel are formed from the solidified material 16, and pellets 18 are embedded therein.
• the nature of the solidified material 16 is selected in accordance with the weight, performance and cost considerations applicable to the intended use of the armor.
• Armor for land and sea vehicles is suitably made using a metal casting alloy containing at least 80% aluminum.
• a suitable alloy is Aluminum Association No. 535.0, which combines a high tensile strength of 35,000 kg/in 2 , with excellent ductility, having 9% elongation.
• Further suitable alloys are of the type containing 5% silicon B443.0. These alloys are easy to cast in thin sections; their poor machinability is of little concern in the application of the present invention.
• An 11 epoxy or other plastic or polymeric material, advantageously fiber-reinforced, is also suitable.
• Pellets 18 have an alumina (AI 2 O 3 ) content of at least 93%, and have a hardness of 9 on the Mohs scale. Regarding size, the majority of pellets have a major axis in the range of from about 3-40 mm, the preferred range being from 6-19 mm for personal armor and lightweight vehicles and the preferred range being from 20-30 mm for protecting light and heavy mobile equipment and vehicles against high caliber armor-piercing projectiles.
• Fig. 1 there are shown in Fig. 1 , for illustrative purposes, a mixture of cylindrical pellets with at least one convexly-curved end face 18a, flat-cylindrical pellets 18b, and spherical pellets 18c. Considerations of symmetry, as well as tests carried out by the present inventor, indicate that the most effective pellet shape is cylindrical pellets with at least one convexly-curved end face 18a. Ceramic pellets are used as grinding media in size-reduction mills of various types, typically in tumbling mills, and are thus commercially available at a reasonable cost.
• pellets 18 are bound by the solidified molten material 16 in a single layer of superimposed rows 20. A majority of pellets 18 are each in contact with at least 4 adjacent pellets.
• the panel 14 acts to stop an incoming projectile 12 in one of three modes: centre contact, flank contact, and valley contact, as described above.
• a pellet 18d having a regular, geometric, prismatic form, with one convex curved surface segment 22.
• Fig. 3 shows a pellet 18e having a circular cross-section 24, taken at line AA.
• the pellet is of satellite form, and is commercially available.
• Fig. 4 illustrates a multi-layered, armor panel 26.
• An outer, impacting panel 28 of composite armor material is similar to panel 14 described above with reference to Fig. 1.
• Panel 28 acts to deform and shatter an impacting high velocity projectile 12.
• Light-weight armor for personal protection is 12
• a tough, yet hard, thermoplastic resin for example, polycarbonate or acrylonite-butadiene-styrene, or epoxy.
• Inner panel layer 30 is adjacent to outer panel 28, and is advantageously attached thereto.
• Inner panel 30 is made of an elastic material, such as multiple layers of Kevlar®, or a material known by its trade name of Famaston.
• inner layer panel 30 comprises multiple layers of a polyamide netting.
• inner panel 30 causes asymmetric deformation of the remaining fragments 32 of the projectile 12, and absorbs remaining kinetic energy from these fragments by deflecting and compressing them in the area 34 seen in Fig. 1. It is to be noted that area 34 is much larger than the projectile cross-section, thus reducing the pressure felt on the inner side 36 of inner panel 30. This factor is important in personally-worn armor.
• Step A a casting mold 38, used for producing a composite armor material 10 as described above with reference to Fig. 1.
• the following elevated-temperature method of manufacture is used: Step A:
• a mold 38 is provided, having a bottom 40, two major surfaces 42, two minor surfaces 44 and an open top 46, wherein the distance between these two major surfaces 42 is 1.2 to 1.8 times the major axis of the pellets 18. For example, 8 mm pellets are used and the distance between major surfaces is 10 mm.
• Pellets 18 are inserted into mold 38 to form a plurality of superposed rows 20 of pellets 18, extending substantially along the entire distance between the minor side surfaces 44, and from the bottom 40 substantially to the open top 46.
• Mold 38 and the pellets 18 contained therein are incrementally heated, first to a temperature of about 100°C, and then further heated to a temperature of at least 100°C above the flow point of the material to be poured in the mold.
• a temperature of about 100°C For example, aluminium has a flow point of about 540°C, and will require heating the mold, together with ceramic pellets contained therein, to above 640°C.
• Step D
• Molten material 16 such as aluminum C443.2 ASTH B 85 or GBD-AISi9Cu2 is poured into mold 38 to fill the same.
• a typical pour temperature range for aluminium is 830-900°C.
• Polycarbonate is poured at between 250-350°C.
• the surfaces of mold 38 are provided with a plurality of air holes 48, to facilitate the escape of air while molten material 16 is poured therein.
• the pellets 18 are slightly rearranged in accordance with the hydrostatic and hydrodynamic forces exerted upon them by the molten material.
• Composite armor material 10 is removed from mold 38.
• the following embodiment of a method of manufacture includes the use of an epoxy resin to form a themoset matrix.
• an epoxy resin to form a themoset matrix.
• epoxies can be cast at room temperature and chemically hardened, or their hardening can be accelerated by the application of heat.
• Epoxy armor is suitable for use on aircraft. Yield strength and Young's modulus are both improved by adding fiber reinforcement.
• Mold 38 having a bottom 40, two major surfaces 42, two minor surfaces 44 and an open top 46, wherein the distance between the two major surfaces 42 is from about 1.2 to 1.8 times the major axis of the pellets 18.
• Pellets 18 are inserted into mold 38 to form a plurality of superposed rows 20 of pellets 18 extending substantially along the entire distance between the minor side surfaces 44, and from the bottom 40 substantially to the open top 46.
• the epoxy is allowed to solidify. 14
• the composite armor material is removed from mold 38.
• a composite armor plate 50 for absorbing and dissipating kinetic energy from high velocity projectiles.
• the plate is provided with a single internal layer of a plurality of high density ceramic bodies 52 bound and retained in panel form by a solidified material 54 such as epoxy.
• the bodies 52 are arranged in a plurality of adjacent rows wherein the pellets 52' along the edge of the plate are in direct contact with four adjacent pellets, while the internal pellets 52" are in direct contact with six adjacent pellets.
• the major axis AA of the pellets 52 are substantially parallel to each other and perpendicular to the plate surface 56.
• Figs. 7a and 7b illustrate impact patterns and measured distances between impact points on two plates prepared according to the present invention and independently tested by Societe A.R.E.S., France.
• Each plate had dimensions of 25x30 cm and a plurality of pellets substantially cylindrical in shape with at least one convexly curved end face, the diameter of each of said pellets being about 12.7 mm and the height of said pellets, including said convex end face, being about 11 mm, said pellets being bound in a plurality of adjacent rows by epoxy, the plate of Fig. 7a having an inner backing layer 12 mm thick, made of Dyneema® and the plate of Fig. 7b having an inner backing layer 10 mm thick, made of Dyneema®.
• the first multi-layered armor panel had a weight of only 38.6 kg/m 2 and the second multi-layered armor panel had a weight of 33.6 kg/m 2 .
• the first panel was impacted by a series of three 7.62x51 PPI projectiles, fired at increasing velocities of 831.1 m/sec; 845.7 m/sec; and 885.8 m/sec at 0 elevation and at a distance of 13 m from the target.
• the second panel was impacted by a series of four 7.62x51 PPI projectiles, fired sequentially at velocities of 783.7 m/sec; 800.2 m/sec; 760.5 m/sec; and 788.4 m/sec at 0 elevation and at a distance of 13 m from the target. 15
• Table 1 is a reproduction of a test report relating to the aluminium matrix multi-layer panel described above with reference to Fig. 4, having a plurality of pellets substantially cylindrical in shape with at least one convexly curved end face, the diameter of each of said pellets being about 9.5 mm and the height of said pellets, including said convex end face, being about 9.5 mm, said pellets being bound in a plurality of adjacent rows by aluminum, and said plate having an inner backing layer, made of Famaston®
• the entire multi-layered armor panel had a total weight of only 34.3 kg/m 2 .
• Table 2 is a reproduction of a test report relating to ballistic resistance tests carried out on a plate, having a plurality of pellets substantially cylindrical in shape with at least one convexly curved end face, the diameter of each of said pellets being about 19 mm and the height of said pellets, including said convex end face, being about 23 mm, said pellets being bound in a plurality of superposed rows by epoxy, and said plate having an inner backing layer 24 mm thick, made of Dyneema®.
• the entire multi-layered armor panel had a total weight of only 80.9 lbs.
• the ammunition used in the first and second test shots was 14.5 mm armor piercing B-32 bullets with increasingly higher values of average velocity, while the remaining test shots fired at the same 24 X 24 inch panel according to the present invention, were with a high-velocity, 20 mm fragment STM projectile.
• the first projectile was fired at a velocity of 3,303 feet per second, followed by a second 14.5 mm armor piercing projectile sequentially fired at a velocity of 3,391 feet per second, followed by two 20 mm fragment STM projectiles fired at average velocities of 4,333 and 4,437 ft/sec, respectively, and only this fourth projectile penetrated the panel, which had already sustained 3 previous hits.
• Thicknesses na Hardness NA Avg. Thick. na in. Plies/Laminates: NA
• Table 3 is a reproduction of a test report relating to ballistic resistance tests carried out on a plate, having a plurality of pellets substantially cylindrical in shape with at least one convexly curved end face, the diameter of each of said pellets being about 19 mm and the height of said pellets, including said convex end face, being about 23 mm, said pellets being bound in a plurality of superposed rows by epoxy, and said plate having an inner layer backing 17 mm thick, made of Dyneema® and a further 6.35 mm thick backing layer of aluminum.
• the entire multi-layered armor panel had a total weight of only 78.3 lbs.
• the ammunition used in the first test shot was a high- velocity, 20 mm fragment STM projectile, while the remaining test shots fired at the same 24.5 X 24.5 inch panel according to the present invention, were with 14.5 mm armor piercing B-32 bullets, with increasingly higher values of average velocity.
• the first projectile was a 20 mm fragment projectile, fired at a velocity of 4,098 feet per second, followed by seven 14.5 mm armor piercing projectiles sequentially fired at velocities from 2,764 to 3,328 feet per second.
• 3328 ft/sec did the eighth armor piercing B-32 bullet penetrate the panel, which had already sustained 7 previous hits.
• CD PER CUSTOMER REQUEST

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• Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
• Laminated Bodies (AREA)

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• 1998
  • 1998-03-30 JP JP2000541474A patent/JP3628257B2/ja not_active Expired - Fee Related
  • 1998-03-30 WO PCT/IL1998/000153 patent/WO1999050612A1/en active IP Right Grant
  • 1998-03-30 TR TR2000/01629T patent/TR200001629T2/xx unknown
  • 1998-03-30 KR KR10-2000-7004414A patent/KR100529535B1/ko not_active IP Right Cessation
  • 1998-03-30 CN CN988106965A patent/CN1082655C/zh not_active Expired - Lifetime
  • 1998-03-30 CA CA002309053A patent/CA2309053C/en not_active Expired - Lifetime

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