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
  • F41H5/0414—Layered armour containing ceramic material
  • F41H5/0421—Ceramic layers in combination with metal layers
• • 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

Definitions

• the present invention relates to an antiballistic garment.
• the present invention relates to an antiballistic garment able to withstand multiple attacks.
• Antiballistic garments are known, and in particular antiballistic jackets, provided with one or more antiballistic protection plates made of ceramic materials able to withstand a mechanical load which acts in a punctiform manner. Such materials are able to absorb large amounts of energy and, at the same time, have a low specific weight compared to the metal materials used before, with obvious advantages.
• an antiballistic garment comprising at least one antiballistic protection plate which in turn comprises at least one layer of ceramic material.
• the ceramic material is of the composite type.
• Said at least one layer of ceramic material is internally reinforced with a metal net which forms at least one layer.
• the metal net is of stretch type with a three- dimensional structure.
• the metal net has a thickness of .0.1 to 6 mm and preferably of 0.5 to 1 mm.
• the thickness is indicated with letter S in Figure 2.
• the metal net has a mesh size of 3 to 30 mm and preferably of 5 to 10 mm.
• the mesh size is indicated with letter D in Figure 2.
• the metal net occupies from 1% to 10% by volume of the composite ceramic body.
• the metal net is coated on the surface with a layer of an oxide and/or a carbide, preferably obtained by anodization, plasma spray method or painting.
• the metal net forms a single layer inside said at least one layer of composite ceramic material.
• the metal net has a coefficient of thermal expansion greater than that of the composite ceramic material.
• said at least one layer of composite ceramic material 3 has a thickness of between 5 mm and 15 mm.
• the thickness of the ceramic body is indicated with letter H in Figure 2.
• the composite ceramic material comprises a vitreous matrix in which ceramic particles are dispersed.
• the ceramic particles dispersed in the vitreous matrix are composed of ceramic oxides, preferably selected from the group consisting of silicates, aluminium silicates and oxides of aluminium, zirconium, chromium, iron and titanium.
• the composite ceramic material comprises a vitreous matrix consisting of a glass having a sodium- potassium, sodium or boric composition.
• the composite ceramic material with ceramic particles dispersed in a vitreous matrix has the composition and structure of a vitrified porcelain stoneware.
• the composite ceramic material with ceramic particles dispersed in a vitreous matrix has the composition and structure of a vitrified porcelain stoneware, enriched with alumina powders, preferably by a percentage by weight of not more than 20%.
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a density of 2.1 to 2.6 g/cm 3 .
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a coefficient of thermal expansion a of 5 to 9 "1 10 ⁇ 6 .
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a hardness of 7 to 20 Gpa measured on the Vickers scale (HV 500g) .
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a modulus of rupture (MOR) of 40 to 60 MPa.
• MOR modulus of rupture
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a modulus of elasticity (MOE) of 25 to 40 GPa.
• MOE modulus of elasticity
• the composite ceramic material has the composition and structure of a porcelain stoneware, preferably with a thermal expansion coefficient a of between 5 and 9 K -1 10 " 6 , and even more preferably equal to 7 K "1 10 ⁇ 6 , and the stretch type metal net with three-dimensional structure is made of stainless steel AISI 430, preferably having a thermal expansion coefficient . equal to 12 K "1 10 ⁇ 6 at 20- 600 °C.
• said at least one antiballistic protection plate comprises a first layer of fibrous material associated to the layer of composite ceramic material on the side thereof facing towards the outside of the garment.
• said at least one antiballistic protection plate may comprise a second layer of fibrous material associated to the layer of composite ceramic material on the side thereof facing towards the inside of the garment.
• said first and/or second fibrous layer is a structure composed of fibres selected from the group consisting of UHMW (Ultra-High Molecular Weight) polyethylene, aramide, copolyaramide , polybenzoxazole, polybenzothiazole, liquid crystal, glass and carbon.
• UHMW Ultra-High Molecular Weight
• said first and/or second fibrous layer is impregnated with polymers selected from the group consisting of thermoplastic, thermosetting, elastomeric, viscous or viscous-elastic polymers.
• the composite ceramic material is a non-oxide ceramic material made of one or more compounds selected from the group consisting of silicon carbide, boron carbide and silicon nitride. DESCRIPTION OF THE DRAWINGS
• Figure 1 shows an antiballistic garment according to an embodiment of the invention
• FIG. 2 shows a schematic sectional view of an antiballistic protection plate according to a first embodiment of the invention
• Figure 3 shows a schematic sectional view of an antiballistic protection plate according to a second embodiment of the invention
• Figure 4 shows a schematic sectional view of an antiballistic protection plate according to a third embodiment of the invention.
• Figure 5 shows a perspective view of an example of stretch net
• FIG. 6 and 7 show two photographs of a protection plate (plate A) of a ballistic element according to a first preferred embodiment of , the invention, respectively before and after firing tests;
• FIGS. 8 and 9 show two photographs of a protection plate (plate B) of a ballistic element according to a second preferred embodiment of the invention, respectively before and after firing tests.
• reference numeral 1 globally denotes an antiballistic garment according to the present invention.
• the antiballistic garment 1 comprises at least one antiballistic protection plate 2, which in turn comprises at least one layer of ceramic material 3.
• the antiballistic garment 1 can be an antiballistic vest or jacket for the protection of an individual's upper trunk.
• the ceramic material is of the composite type. Said at least one layer of ceramic material is internally reinforced with a metal net 4 which forms at least one layer .
• the ceramic material cooperates synergically with the metal reinforcement net, increasing the mechanical resistance of the protection plate of the antiballistic garment, and in particular the ability to withstand multiple attacks.
• the metal reinforcement net has in fact the main function of putting into compression the ceramic material, of retaining the propagation of the fracture and thus it interacts synergically with the ceramic material, reducing the tendency thereof to fragmentation.
• the antiballistic garment according to the invention has a thickness lower than traditional antiballistic garments.
• the metal net is of stretch type with a three- dimensional structure.
• the stretch net is a continuous, seamless structure.
• An example of stretch net is shown in Figure 5.
• the stretch net is obtained by engraving and cold moulding operations of the raw material in rolls or sheets, which give the net a three- dimensional structure.
• the shape of the knives impacting the sheet determines the shape and width of the mesh.
• the three-dimensional structure of the stretch net characterised by a high number of undercuts, allows a homogeneous and deep anchorage between the net and the ceramic material. It is therefore possible to obtain a very cohesive and resistant body, in which the net cannot slide with respect to the ceramic material when the ballistic element is subjected to loads, in particular pulse-type loads, such as bullet hits.
• the net can have any mesh geometry.
• the mesh geometry is polygonal and thus provided with corners to increase the points of adhesion with the ceramic material.
• the mesh geometry can be square, hexagonal or rhomboidal.
• the metal net has a thickness of 0.1 to 6 mm and preferably of 0.5 to 1 mm.
• the metal net has a mesh size of 3 to 30 mm and preferably of 5 to 10 mm. It has been verified that a mesh too large increases the fracture propagation and a mesh too small does not integrate well into the ceramic, tending to split it.
• the metal net 4 occupies from 1% to 10% by volume of the composite ceramic body.
• the stretch net 4 can be made of any metal.
• the metal net is made of a material selected from the group consisting of iron, stainless steel, titanium, molybdenum, aluminium, copper, brass.
• the stretch metal net does not change its features at the temperatures of the formation process of the ceramic material in which it is inserted.
• the metal net must not react by crystallising with the ceramic material.
• the metal net may be coated on the surface with a layer of an oxide and/or a carbide. This coating has the function of inerting the metal net,, reducing the aggressiveness of the ceramic material on the same net.
• the oxide and/or carbide layer can be obtained through anodization (standard or PEO, Plasma Electrolytic Oxydation) , plasma spray method or painting.
• the metal net 4 forms a single layer inside said at least one layer of composite ceramic material 3.
• the three-dimensional structure of the stretch net without junctions, in fact ensures a reinforcement capacity greater than the nets traditionally used, thus allowing the use thereof in a single layer rather than in a plurality.
• said at least one layer of composite ceramic material has a thickness of between 5 mm and 15 mm.
• the ceramic body is preferably reinforced by a plurality of layers of metal net .
• the metal net has a coefficient of thermal expansion greater than that of the ceramic material with respect to all ceramic materials.
• the coupling between the ceramic material and metal net can generate within the composite ceramic material compressive stress states functional to the improvement of the mechanical features of the material ' itself. Thanks. to the fact that the ceramic body has a thermal expansion coefficient lower than that of the metal net and since the ceramic material is obtained through a thermal treatment, upon cooling of the body, the metal net has a more pronounced shrinkage compared to the ceramic material. This causes on the ceramic material a compressive stress state which improves the hardness and impact resistance features.
• the composite ceramic material comprises a vitreous matrix in which ceramic particles are dispersed.
• the ceramic particles dispersed in the vitreous matrix are composed of ceramic oxides, preferably selected from the group consisting of silicates, aluminium silicates and oxides of aluminium, zirconium, chromium, iron and titanium.
• the composite ceramic material comprises a vitreous matrix consisting of a glass having a sodium- potassium, sodium or boric composition.
• the composite ceramic material with ceramic particles dispersed in a vitreous matrix has the composition and structure of a vitrified porcelain stoneware.
• the vitrified porcelain stoneware comprises silicon dioxide (Si0 2 ) with a percentage by weight of between 66% and 72%.
• the vitrified porcelain stoneware comprises alumina (A1 2 0 3 ) with a percentage by weight of between 19% and 25%.
• the vitrified porcelain stoneware comprises potassium oxide (K 2 0) with a percentage by weight of between 1.5% and 2%.
• the vitrified porcelain stoneware comprises sodium oxide (Na 2 0) with a percentage ' by weight of between.3% and 5%.
• the vitrified porcelain stoneware comprises a mixture of calcium oxides (CaO) and magnesium (MgO) with a percentage by weight of less than 1%.
• the vitrified porcelain stoneware comprises a mixture of iron oxides (Fe 2 0 3 ) and titanium () with a percentage by weight of less than 1%.
• the vitrified porcelain stoneware comprises zirconium oxide (Zr0 2 ) with a percentage by weight of between 3% and 6%.
• the vitrified porcelain stoneware has the following composition (percentages by weight): Si0 2 66-72%; A1 2 0 3 19-25%; K 2 0 1.5-2%; Na 2 0 3-5%; CaO+MgO ⁇ 1%; Fe 2 0 3 +Ti0 2 ⁇ 1%; Zr0 2 3-6%.
• the composite ceramic material with ceramic particles dispersed in a vitreous matrix has the composition and structure of a vitrified porcelain stoneware, enriched with alumina powders.
• the percentage by weight of alumina powders is not more than 20%.
• the vitrified porcelain stoneware enriched with alumina powders comprises S1O 2 with a percentage by weight of between 53% and 60%.
• the vitrified porcelain stoneware enriched with alumina powders comprises Al 2 0 3 with a percentage by weight of between 34% and 42%.
• the vitrified porcelain stoneware enriched with alumina powders comprises K 2 0 with a percentage by weight of between 1% and 2%.
• the vitrified porcelain stoneware enriched with alumina powders comprises Na 2 0 with a percentage by weight of between 2.5% and 4%.
• the vitrified porcelain stoneware enriched with alumina powders comprises CaO+MgO with a percentage by weight of less than 1%.
• the vitrified porcelain stoneware enriched with alumina powders comprises Fe 2 0 3 + i02 with a percentage by weight of less than 1%.
• the vitrified porcelain stoneware enriched with alumina powders comprises Zr0 2 with a percentage by weight of between 2% and 5%.
• the vitrified porcelain stoneware has the following composition (percentages by weight) : S1O 2 53-60%; AI2O3 34-42%; K 2 0 1-2%; Na 2 0 2.5-4% ; CaO+MgO ⁇ 1%; Fe 2 0 3 +Ti0 2 ⁇ 1%; Zr0 2 2-5%.
• the composite ceramic material with ceramic particles dispersed in a vitreous matrix having the composition and structure of a vitrified porcelain stoneware is made by powder sintering.
• the production process is by axial moulding.
• the operating conditions are as follows :
• the production process can be by casting (in pressure or not).
• the operating conditions are as follows:
• the metal net (in a single layer or multiple layers) is arranged inside the mould. If a single layer of metal net is inserted, arranged for example halfway of the layer of composite material, the mould is loaded with the powder or the slurry to half its weight; at this point, the net is arranged and then the remainder of the powder charge or slurry. Then, the subsequent operations of forming of the ceramic body are carried out.
• the powder charge or slurry can also be split into unequal parts, depending on the position that the net must have within the ceramic body.
• standard particle sizes are adopted for the powders in the production of porcelain stoneware.
• the finest particle size profiles are adopted. In fact, it was found that the finer the particles the better the antiballistic properties of the composite obtained.
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a density of 2.1 to 2.6 g/cm 3 .
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a coefficient of thermal expansion a of 5 to 9 K "1 1CT 6 .
• the vitreous-ceramic composite consisting of vitrified .porcelain stoneware has a hardness of 7 to 20 Gpa measured on the Vickers scale (HV 500g) .
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a modulus of rupture (MOR) of 40 to 60 MPa.
• MOR modulus of rupture
• the vitreous-ceramic composite consisting of vitrified porcelain stoneware has a modulus of elasticity (MOE) of 25 to 40 GPa.
• MOE modulus of elasticity
• the . vitreous-ceramic composite has a very low porosity.
• the porosity is less than 5%. Even more preferably, the porosity is less than 2%, and much more preferably less than 0.5%.
• the porosity is a measure of the internal voids of a material. Typically, there are two types of porosity: open porosity and closed porosity. "Open porosity" is when there are internal pores interconnected to one another and connected to the ⁇ surface; on the other hand, “closed porosity” is when there are no internal pores interconnected to one another. Generally, percentages of porosity of less than 2% give a closed porosity .
• a material substantially free of open porosity does not absorb water and/or humidity. It is therefore possible to exclude the risk of corrosion attacks to any metal materials incorporated in the material.
• a low porosity improves the properties of mechanical resistance to impulsive impacts.
• said at least one antiballistic protection plate 2 comprises a first layer of fibrous material 5 associated to the layer of composite ceramic material 3 on the side thereof facing towards the outside of the garment.
• the first fibrous layer has the function of containment of the fragments.
• said at least one antiballistic protection plate 2 may comprise a second layer of fibrous material 6 associated to the layer of composite ceramic material 3 on the side thereof facing towards the inside of the garment.
• the function of the second fibrous layer is, in addition to the containment of the fragments, to dissipate the impact energy of the projectiles transmitted by the layer of ceramic material to reduce the effects thereof on the user, and thus the resulting trauma .
• said first and/or second fibrous layer is a structure composed of fibres selected from the group consisting of UHM (Ultra-High Molecular Weight) polyethylene, aramide, copolyaramide , polybenzoxazole, polybenzothiazole, liquid crystal, glass and carbon.
• UHM Ultra-High Molecular Weight
• UHMW polyethylene fibres such as Dyneema® or Spectra® fibres .
• said first and/or second fibrous layer is impregnated with polymers selected from the group consisting of thermoplastic, thermosetting, elastomeric, viscous or viscous-elastic polymers.
• polymers selected from the group consisting of thermoplastic, thermosetting, elastomeric, viscous or viscous-elastic polymers.
• the impregnation with the above polymers imparts rigidity to the fibrous layer, increasing the capacity thereof of energy dissipation.
• the composite ceramic material can be a non-oxide ceramic material made of one or more compounds selected from the group consisting of silicon carbide, boron carbide and silicon nitride.
• the antiballistic protection plates were placed on a backing of Dynaema, packaged with a transparent stretchable film to not disperse the plate fragments after firing, and positioned on a target of plasticine.
• the tests were carried out by firing with a barrel gauge at a distance of 10 m projectiles caliber 7.62x51 FMJ nato ball with a speed of 830 m/s and projectiles caliber 7.62x39 with soft iron core with a speed of 730 m/s.
• two plates were tested, of dimensions 250 x 300 mm made of composite ceramic - material of vitrified porcelain stoneware, enriched with alumina powders. Both plates had .an average thickness of about 5 mm and were provided with a stretch steel metal net with thickness of 0.8 mm and with rhomboidal meshes 16 x 8 mm. The nets had dimensions of 232 x 276 mm, a weight of 108.9 g equal to 1.70 Kg/m 2 .
• Plate A had an average thickness of 5.40 mm and a weight per surface area of 13.30 Kg/m 2 .
• Plate B had an average thickness of 5.50 mm and a weight per surface area of 13.50 Kg/m 2 .
• Figures 6 and 7 show two photographs of the protection plate A respectively before and after the firing tests; Figure 7 shows with letters a-h the points of impact of the shots fired.
• Figures 8 and 9 show two photographs of the protection plate A respectively before and after the firing tests; Figure 9 shows with letters a-e the points of impact of the shots fired.
• the stretch metal net although not well incorporated or slightly melted, is able to retain the fracture of the plate after the first shot.
• the plate remains intact with small diameter holes. This allows the plate to withstand and stop many shots even very close together, preventing any trauma in the case of plate A with shots 7.62x51 FMJ nato ball 9.6 g or maintaining a constant trauma in the case of plate B.
• said at least one layer of the antiballistic protection plate is made of composite ceramic material with the composition and structure of a vitrified porcelain stoneware, preferably having a thermal expansion coefficient a of between 5 and 9 K -1 10 " 6 , and even more preferably equal to 7 ⁇ 1 10 ⁇ 6 .
• the vitrified porcelain stoneware has a composition according to one of the alternatives described above and is produced according to one of the two methods defined above.
• Said at least one layer of composite ceramic material of vitrified porcelain stoneware is internally reinforced by a stretch type metal net with three-dimensional structure, arranged to form at least one layer inside the ceramic material.
• the net is made of steel AISI 430 (ferritxc stainless steel), preferably having a thermal expansion coefficient a equal to 12 K "1 10 "6 at 20-600 °C.
• test plates made according to this combination showed significantly less marked and extensive fracture conditions than the comparison plates, as proof of the superior properties of antiballistic protection.
• the comparison was made with plates made of the same composite ceramic material, but in which the reinforcement net was made with the following steels: a. AISI 304 stainless steel with chromium and nickel, austenitic, with thermal expansion coefficient a equal to
• the coefficient of steel should also not be too close to that of ceramic, otherwise the mechanical properties required to withstand the stresses caused by the projectiles are not achieved.
• the stainless steel AISI 430 seems to be the steel that provides the best dilatometric agreement with the vitrified porcelain stoneware and thus, the more marked reduction of the residual stresses in the ceramic-net assembly at the end of the production process, which in particular provides for the baking of the material.
• the antiballistic garments according to the invention are able to offer a capacity of resistance to attacks of multiple type comparable to that of traditional antiballistic garments, but with lower thickness. This is essentially linked to the fact that the integration into the ceramic material of the reinforcement net determines a lower tendency to fracturing under impulsive hits.
• the antiballistic elements according to the invention have lower weights.
• the invention is therefore able to meet the need in the field to have antiballistic garments, and in particular antiballistic jackets, which combine low weight and adequate antiballistic properties in terms of ability to withstand multiple attacks.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Laminated Bodies (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)
• Detergent Compositions (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Compositions Of Oxide Ceramics (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=50031420

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (9)

• 2013
  • 2013-11-14 IT IT000166A patent/ITBS20130166A1/it unknown
• 2014
  • 2014-11-14 WO PCT/IB2014/066042 patent/WO2015071866A1/fr not_active Ceased
  • 2014-11-14 EP EP14812630.3A patent/EP3069097B1/fr active Active

Also Published As

Similar Documents

Legal Events