WO2019038720A1

WO2019038720A1 - Transparent multi-hit armor

Info

Publication number: WO2019038720A1
Application number: PCT/IB2018/056404
Authority: WO
Inventors: Mario Arturo MANNHEIM ASTETE; Pierre MEZEIX
Original assignee: AGP America SA
Current assignee: AGP America SA
Priority date: 2017-08-23
Filing date: 2018-08-23
Publication date: 2019-02-28
Anticipated expiration: 2020-02-23
Also published as: CO2017012225A1

Abstract

The present invention relates to a special array of materials of a transparent armored composition, for transportation and architectural applications. The materials are layered and can be made of different organic or inorganic materials including glass, glass-ceramic, polymeric materials, transparent ceramic, monocrystal. The layered materials are plastic bonded together by a polymeric material, wherein weak spots are patterned at the surface or embedded within the volume of any of the layers of the laminated armor, improving the behavior upon multi-hit attacks. This behavior is obtained by creating a pattern of weaknesses either at the surface or embedded within the volume of any of the layers of the laminated armor. The weakened pattern can be obtained by different processes, including but not limited to ion-exchange, thermal tempering, scratching/abrasion and laser. The laminated structure benefits from the heterogeneous layers by offering good visibility before and after as well as better performance against multi-hit penetration.

Description

TRANSPARENT MULTI-HIT ARMOR

Field of the invention The present invention relates generally to transparent armored laminates for transportation and architectural applications, wherein the laminate behavior is controlled upon multi-hit attacks, by incorporating patterned weakened spots at the surface or within the volume of any of the layers of the laminates. Background of the Invention

Transparent armor has been used since WWII, both for military and nonmilitary applications. Such armors are generally used as windows for ground, marine vehicles and aircraft. Such armors may also be used for architectural applications such as transparent windows, doors, roofs or transparent walls.

These compositions conventionally consist of a set of hard transparent layers joined together by polymeric and thermoplastic polymeric layers in a sandwich-like configuration. Hard materials may be comprised of glass, glass-ceramic, polymeric material or transparent ceramic. These layers are generally bonded together by one or several polymeric layers such as Polyvinyl Butyral (PVB), Poly-Urethane (PU) or Ethylene-Vinyl Acetate (EVA), which are adhesive interlayers. In some cases, the use of such interlayer can be avoided using acrylic based solutions, such as those illustrated in documents US 5,506,051 A; US 7,318,956 B2; US 8,119,231 B2 or an ionomer layer such as those disclosed in US 7,919,175 B2.

Among currently used transparent armored compositions, the architecture of a bullet-resistant composite commonly found in the art will be described making reference to FIG. 1. Starting from outside to inside ("outside" meaning the space from where a bullet is normally shot from; likewise, "inside" refers to the space protected by the bullet-resistant composite). A strike-face layer 100 which receives the projectile impact is found, which is fixed to other hard intermediate layers (interlayers) 101 by means of several layers of adhesive materials 130 and a backing plastic layer 120 made of any high impact resistance plastic material constituting the "spall-shield" or anti-splinter layer, a soft material, typically PC or acrylic. The material and thicknesses used for the layers are chosen depending on the mechanical properties of said material, the function of the layer within the structure and desired resistance. Generally, armored compositions are comprised by different layers of different or similar thicknesses. Generally, the outer layer or strike -face layer is made of hard materials such as glass (for example as those illustrated in document US 6,708,595 Bl ; US 2008/0092729 Al; US 2015/0000511 Al ; US 5,747,170), glass-ceramics (US 8,176,828 B2; US 8,161,862 B l; US 8,603,616 B l; US 2010/0275767 Al ; US 2014/0162039 Al, US 7,875,565 Bl), or ceramics (US 7,584,689 B2; US 8,297,168 B2).

One of the most relevant mechanical properties considered for the selection of material to be used in the strike-face layer of the composite of bullet-resistant glass is hardness. Hardness could be understood as a measure of how much force is required to permanently change the shape of a material. Accordingly, it is desirable to provide a harder material in order to erode or remove material from a softer material. In the present invention, the role of the strike-face layer is to erode and deform the projectile materials, strip mass away from it and thus reduce its kinetic energy.

Nevertheless, glass materials with Vickers Hardness < 10 GPa are inefficient at eroding and deforming Armor-Piercing ammunition (AP) composed of a hard-core material. Against this type of threat, harder materials may be used, such as transparent ceramics, glass-ceramics, and monocrystals.

The role of the glass intermediate and internal layers is to lessen the velocity of the projectile. This can be achieved by providing a plurality of glass layers. The internal layers are generally made of a hard material such as glass or glass-ceramic and are adhered together by Polyvinyl Butyral (PVB) or Polyurethane (PU) interlayers.

The last part of the armor, which is called the backing layer or spall-shield, is generally composed of one of several layers of soft materials with a greater capacity in order to deform the mass of the projectile. Polycarbonate (PC) or acrylic are among the plastic materials which have been shown to be as efficient as spall-shield layers. The role of the backing layer is to absorb the remaining energy of the projectile by plastic deformation (strain), as well as preventing shards and shrapnel from penetrating the bullet-resistant composition.

Several variations of this typical design may be formed. In some embodiments, an air gap can be found in the armor panel, which improve the heat and/or ballistic resistance as illustrated in US 8,281,550 B l; US 2014/0013932 Al ; US 2011/0072961 Al; US 8,898,966 B2; US 6,818,268 B2; US 2012/0269995 Al. Additional configurations and architectures may include a thin cover glass placed over the strike-face facing the exterior side of the transparent armored laminates, as illustrated in US 2012/0174761 Al which can help to destroy the jacket of the projectile. Other designs are composed of non-parallel layers as illustrated in US 2011/0308381 Al ; US 2014/0013932 Al which can help to increase the ballistic performance without adding weight to the structure.

Additional geometries may include heterogeneous or non-dense layers, which can consist of fibers (US 2010/0330341 Al), rods (US3573150 A) or tiles (US 2008/0092729 Al ; US 7,681,485 B2; US 2015/0024165 Al ; US 2009/0320675 Al).

The use of tiles is especially useful against multi-hits attacks. Indeed, by reducing the damages of the structure to the impacted and surroundings tiles, both the visibility and penetration resistance after-hit can be preserved, thus remaining efficient against next impacts. This has been well known and largely applied in the case of opaque armors and many examples of tile structures of many shapes and geometries can be found, as illustrated in US 6,532,857 B l ; US 6,332,390 B l; US 7,311,790 B2; US 8,215,223 B2; US 5,847,308; US 6,135,006; US2002/0178900 Al; US2004/0028868 Al ; US 5,114,772 A; US 4,948,673 A; US 5,326,606 A; US 5,686,689 A; US 2009/0229453; US 2009/0078109 Al ; US 2008/0236378 Al ; US 7,703,375 Bl.

Another reason to use tiles or separated modules to form an armor panel may be to reduce the cost of production. Indeed, some materials, especially ceramics can be very difficult and expensive to produce in large pieces. This remark is even truer in the case of transparent ceramics panels which to this day cannot be manufactured in a reasonable cost in surface areas greater than 500 x 500 mm² Nevertheless, the visibility of the joints between the tiles remains one of the major problem coming from the use of individual tiles/modules for transparent armors. The joints between the separated parts can indeed greatly disturb the visibility through the panel and even lead to motion sickness when used as windshield/vehicle window. Solutions to reduce the joint visibility include polishing the edges of the tiles and fusing them together by subjecting them to high temperature/pressure, as illustrated in US 2012/0196105 Al. Another solution consists in polishing the edges and gluing the tiles together with a material of similar refractive index as the materials making up the tiles, as illustrated in US 7,681,485 B2. These two solutions greatly increase the costs and time of production.

Brief summary of the invention

The present invention relates to transparent armor laminates comprising at least one layer having a weakened area that upon impact provides a controlled fracture of the layer and a method for producing the same. The layer having the weakened area is made from a unique panel and subjected to a specific process in order to create a pattern embedded within it, or at its surface, resulting in a controlled fracturing upon impact of a projectile. The present invention prevents crack propagation to the panel by guiding them throughout a specific weakened pattern. The weakened pattern consists of weaker area or spots at the surface or embedded within the volume of the panel. It has been found that the configuration of the laminates of the present invention is the tiles-structure behavior that remarkably increases the multi-hit performance without the need to bond together multiple individual tiles, but rather with one unique panel to be "separated" upon impact. The panes with tiles embedded normally generate distortions or generate problems with visibility at the "fictive joints". The present invention improves the visibility through the panes of the "fictive joints" without any special treatment, such as fusing or gluing the tiles together.

Another aspect of the present invention is the variety of patterns that can be embedded in the panels of the transparent armor. As there is no need to manufacture individual parts, there is no limit to the sizes, shapes or diversity of the pattern array of the weakened area. In another aspect of the invention, different methods can be used to embed such patterns in the transparent armor's panels depending on the material used for the layer which will be subject to the weakening process. Such methods can be classified into different categories, as follows: i) different stress conditions; ii) defects generation, and iii) composite materials. Some of these methods may be applied directly during the weakening process.

The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operations of the invention.

Brief description of the drawings

FIG. 1 is the isometric view of a prior art example of transparent armor laminate.

FIG. 2 is the isometric view of an example of transparent armor laminate showing weaken spots.

FIG. 3 is the isometric view of an additional example of transparent armor laminate with more interlayers showing the weakened spots.

FIG. 4 is an example of an additional embodiment of a transparent armor laminate.

FIG. 5 is the front view of glasses with different weaken patterns.

FIG. 6 is the front view of glasses with different weaken patterns and showing a single impact.

FIG. 7 is a side view of the weakened layer, scratching process.

FIG. 8 is the side view of the weakened layer during the laser process.

FIG. 9 is the side view of the weakened layer during material inclusion.

FIG. 10 is the side view of the weakened layer, IOX or thermal process.

FIG. 11 is the isometric view of inclusion by expanded fibers system.

Reference numerals of drawings 100: Strike-face layer

101 : Intermediate layer

120: Backing plastic layer.

130: adhesive materials 111 : Pattern or weaknesses

140,150: materials of the intermediate layer

160: hard material layer

201 : Scratching tool

202: Tool or mask

203: Laser

204: Pulverization tool

205: Holding tool

210: Scratch

220: Stress profile

230: Defects

240: Particles

250: Fiber Detailed description of the invention

Referring to FIG. 1 , a typical transparent armored laminate is shown, in which each one of the differentiated layers in FIG. 1 has a specific function from a ballistics perspective. The first layer or strike-face layer 100, corresponds to the external layer of the panel and is comprised of a series of glass layers bonded together by the use of polymeric adhesives. The strike -face layer 100 works as a set which absorbs the greatest amount of projectile energy and its surface area depend on the window size. In some embodiments, the thickness of the strike-face layer 100 can range from a few millimeters to a few centimeters, depending on the application. Intermediate layers 101 can be generally made of hard materials such as glass (soda-lime, aluminosilicate or borosilicate) or glass-ceramic. The strike-face layer 100 and intermediate layers 101 have also the function of a highly elastic body which absorbs projectile residual energy. The intermediate layers 101 are bonded together with polymer adhesive materials 130 which bond them. In the transparent armored laminate shown in FIG. 1, the laminate comprises three intermediate layers 101 made of glass, however, it should be noted that the intermediate layers 101 can be composed of any number of intermediate layers, i.e. the intermediate layers can vary from 0 to 20. A backing plastic layer 120 made of any high impact resistant plastic material, reduces the spread of cracks and increases the bullet-resistant composite's capability to resist multiple impacts by maintaining together all layers making up the composite. Materials most used to bond layers are: Polycarbonate (PC) or Polymethyl methacrylate (PMMA), additional materials such as polyurethane (PU), ethylene vinyl acetate (EVA), ionomers, and polyvinyl butyrate (PVB), or special PVB, PU or other polymers can also be used. All these layers have generally a thickness ranging from 1 to 20 mm.

The transparent armored composition of the present invention comprises at least one layer subjected to a weakening procedure as shown in FIG.5 and FIG.6. As will be explained, different patterns 111 of any form and shape can be embedded over or within the surface of any of the glass layers (v.g. strike face layer 100, intermediate layer 101), and such layers can be located anywhere in the laminates. The weakened pattern 111 has the purpose to force the breakage of the layer along those patterns 111 and limit the crack and wave propagation of an impact. FIG. 6 illustrates some examples of impacts on different pattern 111 geometries.

Referring to the embodiment illustrated in FIG. 2, the composition comprises a strike-face layer 100 subjected to a weakening process, in which the tiles-like pattern 111 processes will be applied. It should be noted that one or multiple layers (v.g. strike face layer 100, intermediate layer 101), of the composition can be subjected to different weakening process, creating different weakened patterns 111 through the glass composition. The layer or layers subjected to a weakening process can be made of glass, glass-ceramic or transparent ceramic. Transparent ceramic refers to any inorganic material which is transparent and has a crystalline structure, whether polycrystalline (for example Spinel, YAG, AION) or monocrystalline (Sapphire). Also, in FIG. 2 is shown a backing plastic layer 120 is bonded to an intermediate layer 101 by an adhesive material 130. Particularly, in FIG. 3 is shown an embodiment of the armored composite of the present invention comprising six intermediate layers 101 bonded together with adhesive materials 130. Different patterns 111 of shapes and contours can be applied over the surface of the strike -face layer 100, like the ones shown in FIG. 5. If regular patterns 111 are not preferred, any irregular pattern 111 that can be imagined can be used.

Nevertheless, from a ballistic point of view, the embodiment with 6-edges hexagons pattern 111 would be the most efficient. Regular square-grid pattern 111 may also be preferred because of their simplicity.

It should be noted that the present invention can be composed of any kind of glass materials in any configuration. For instance, the armored glass composition can be provided with different materials in the intermediate layers 101, strike-face layer 100 and the backing plastic layer 120. For instance, the embodiment illustrated in FIG. 4, shows a strike-face layer 100 adhered to a hard material layer 160 by an adhesive material 130. The hard material layer 160 serves as a protecting layer, the intermediate layers 101 can be composed of any material, such as those of ceramics, vitro-ceramics, or any organic/inorganic material. The embodiment illustrated in FIG. 4 shows a composition with an intermediate layer 101 composed of several materials 140, 150 that are of different thicknesses and materials (v.gr. those materials can be of glass and other can be composed of glass ceramics). Likewise, the composition can have different adhesive materials 130 between the layers (v.g. strike face layer 100, intermediate layer 101, backing plastic layer 120) and can be of different thicknesses.

Furthermore, it should be noted that the crack velocity upon impact is much less than the Shockwave, which spread at the speed of sound (4000-6000 m/s in glass). For instance, the crack velocity has been measured to an average of 1920 m/s in borosilicate glasses impacted at high speed (600-900 m/s) (Andersan, Bigger, & Weiss, 2014). In an additional study, the crack, transversal and longitudinal wave velocities are found to be respectively 1580 m/s, 3518 m/s and 5763 m/s for soda-lime glass (Strassburger, Patel, McCauley, & Templeton, 2007).

The shock wave, going faster than the cracks, will be likely to break the glass at the pattern array of the weakened area, thus isolating the impact zone from the rest of the layer. Hence, cracks will not be able to propagate to the full layer, exhibiting a fracture patterns 111 of the strike-face layer as indicated in FIG. 6. In the case where the shock wave is not sufficient enough to break the glass along the desired pattern 111, cracks will likely be guided through it. In any case, the damage of the layers will be diminished to the close area of the impact zone. This will result in further damage of the impacted zone, especially if the shock wave breaks the glass at the pattern 111. In that case, the shock wave will mainly reflect on the newly created edge. As a result, the composition will probably have a lower single-hit performance, which could be compensated by larger thickness, but much better multi-hit performance.

The present invention discloses different methods to embed or generate weak spots and/or weakened areas within or at the surface of the material. Some of these methods are the following: induction of internal stresses by ion-exchange or thermal expansion differences; induction of new surfaces by introducing defects at the surface by a scratching process or within the glass by laser; and creation of an interface with another material/phase, by phase separation or material introduction.

Different stress conditions:

By heterogeneous ion-exchange treatment. A cover is applied to the surface of the layer where the ion exchange treatment is not to be applied. Such a cover serves as a Tool or mask to create the stress profile heterogeneities and blocks the ion-exchange along the area of the surfaces where the desired pattern is to be applied.

By thermal treatment. This is the same idea as the previous method of creating a heterogeneous pattern of stress at the surface of the layer. By heating or cooling the surface of the layer at a different rate at the same time, heterogeneous stresses can be initiated at the surface of the material (only with a material with a large enough coefficient of thermal expansion).

Defects generation:

- By scratching. In that case, the surface of the layer that is subjected to the weakening procedure is scratched along the desired pattern. The surface may be slightly polished after scratching in order to smooth the edges of the scratches and increase the visibility. By laser. A laser can be used to create defects/flaws within the layer along the desired pattern.

Composite material:

By phase separation. Using a thermal source, crystallization/phase separation can be initiated along a desired pattern embedded within the layer subjected to the weakening process. When subjected to a high temperature, generally above the glass transition temperature, crystallization occurs within the glass. That is to say crystallites nucleate and if they have a size big enough they can grow into a crystal. This nucleation/growth process (including velocity, size, and composition of crystals) depends on the glass composition, the temperature, the atmosphere and the ambient pressure, it can be homogeneous or heterogeneous. It means that the crystallization can be controlled locally by adjusting these parameters, such as temperature and time. Subjecting the glass surface to a temperature just below the crystallization temperature and increase it slightly locally where is wanted that the pattern to be could lead in the desired effect, nucleating crystals along the desired pattern. It should be noted that the same principle works for different materials, not just glass.

By other material inclusion. Additional materials may be included to the panel in order to create an interface along the desired pattern. This additional material can be of different nature (organic, inorganic) and shapes (rods, fibers, particles). One of the methods to process this inclusion would be to heat a first material subjected to the weakening process to a temperature high enough so that the viscosity of that first material (the panel or layer) is low enough to allow penetration without breaking the second material. The second material may be pressed or sprayed within the first one. The employment of these methods would depend on the material that is going to be subjected to the weakening process. A person versed in the art would understand that each one of these processes would have different effects and results.

A key aspect of the invention is to ensure the transparency of the armored glass composition. One of the objectives of this processing is to have weakened areas invisible to the observer. Depending on the method performed, the results can be more or less efficient, and more or less imperceptible. In the following paragraphs, it will be described each method individually.

Scratching the surface of the layer (v.g. strike face layer 100, intermediate layer 101) might be one of the most obvious and easier processes as illustrated in FIG. 7. This method can be done by using an indenter, blade or any cutting or scratching tool 201 of any material. Using an automatic tool with 2D scattering (2 dimensions Computer Numerical Controlled (CNC) machine) to scratch the glass along the desired pattern 111 would make the process fast and precise.

Additional embodiments would include a 6-axis CNC tool to generate complex surfaces such as curved surfaces. The depth of the scratch 210 can range from a few μπι to few mm , depending on the material, desired efficiency, and visibility. It might be advantageous to improve the appeal of the layer (v.g. strike face layer 100, intermediate layer 101), by slightly polishing the edges (mechanically or chemically), resulting in a smooth surface of the edges of the cracks. In some embodiments, the depth of the scratch 210 ranges from 5 μπι to 1 mm.

If the processed layer is used as a strike-face layer, it might be useful to cover it with an additional hard material layer, which in preferred embodiments, can only be of a few mm thick, and would serve as a protective layer, in order to make sure that no mechanical (i.e., dust, rocks, debris) or chemical (i.e., water, cleaning product, salt water) attack would induce or propitiate the activation of the crack failure (v.gr., a high-speed impact) and cause the weakened pattern 111 to crack before a non-ballistic attack, reducing the lifetime of the glass assembly.

The weakened pattern can also be generated by the use of a laser, resulting in defects 230 as illustrated in FIG. 8. Those defects 230 can be embedded at the surface or within the strike- face layer 100 using a source of laser 203. Several patents related to scribing, cutting or engraving glasses with lasers exist such as US 8,932,510 B2; US 2007/0051706 Al ; US 2011/0127242 Al ; and US 2013/0323469 Al. Also patents related to some additional methods consisting of creating defects within the strike-face layer 100 using a laser exist such as US5637244 A; and US6333486 Bl. Forming glass filaments within the layer is also known in the prior art as illustrated in US 2015/0034613 A 1.

As stated before, surface defects can be generated at the surface of the material along a desired pattern 111. Those defects can consist in complete lines, separated lines, or dots, which can be generated or embedded within the surface of the material (sub-surface). Depending on the technique used to create the defects, they can have different sizes, shapes, and spacings. The objective is to keep the defects invisible to the observer, but large (and close to one-another) enough to obtain the desired effect (guiding/stopping shock wave and cracks upon impact). An additional method to generate weakened areas would consist of initiating phase separation along a desired pattern 111. The phase separation method can take place in the case of glasses and glass-ceramics for example by heating the material, locally, close to its crystallization temperature. The method provides a local source of energy that allows for locally controlled crystallization on desired spots. Such a source can be a laser or any source. Depending on the material used, the crystallization can be smartly controlled in order to create small enough crystallites are invisible to the naked eye.

Another method would consist in including a foreign material within the layer. This can be done with sufficient pressure and temperature. In the case of glass, for example, the temperature can be elevated so that the viscosity of the glass is small enough for this. Additional materials can be included but not limited to ceramic, glass, metals, and polymers.

Furthermore, particles of the same material can be included within the glass as the processed layer (v.g. strike face layer 100, intermediate layer 101). In one embodiment, the pattern 111 is an interface can be created between the material consisting the first layer and the included new material. Particles 240 of this new material can be pulverized/sprayed by a pulverizing tool 204 as illustrated in FIG. 9 with a force sufficient enough that allow for its penetration within the processed layer. An additional method to introduce defects on the materials subjected to the weakening procedure could consist in extended fibers 250 inclusion as illustrated in FIG. 11. In this system, if the viscosity of the processed material that is going to have a weakened area is small enough, fibers 250 of said material to be included could be stretched and "pushed" into the material to be processed. However, fibers 250 can be provided to form any shape and size desired, so as to be made to conform to the shape of the assembly. The system of FIG. 11, may include a holding tool 205 which pulls any kind of fiber 250 (i.e., steel, glass fiber 250, textile, etc.) over a hard-transparent material or glass strike face layer 100. Then, the strike face layer 100 is subjected to high temperature enough so that its viscosity allows the fiber 250 to enter the material. This method of generating patterns 111 with straight lines running from one edge to another of the panel would be preferred. Other mechanical methods for creating weakened areas would not be the creation of interfaces within or at the surface of the strike-face layer 100 but rather by creating a difference in the stress state of the material. This can be done by ion exchange or thermal tempering. An ion-exchange process is a well-known method for strengthening a glass through which ions of a certain size are extracted from glass or glass-ceramic and other larger ones are introduced. The process emerges as an alkali glass within a salt bath (KNO3) and keeping it at high temperature for several hours. The incorporation of larger ions into the molecular structure of glass and glass-ceramics generates compression stresses on the glass or glass-ceramic surface. The thickness of the compression stress generated is known as "case depth or Depth of Layer - DOL" and represents the depth reached by those larger ions through the glass or glass-ceramic surface. The prior art discloses the relationship that exists between ion exchange and ballistic properties of glass and glass-ceramics.

This residual compressive strength strengthened the layer at its surface by limiting the formation and growth of cracks. On the other hand, this also creates a tensional zone located below the compression zone. The tensional zone is weaker than the rest of the material. The present invention performs the ion exchange process to only on certain spots of the layer surface, in order to create different patterns 111 of weaknesses. An example of this embodiment is illustrated in FIG. 10 where stress profile 220 is represented by the limit between the compressive and the tensile stress. In order to carry out this process, in one embodiment, the pattern 111 would be blocked by limiting the contact between the material and the salt bath at this spot, by using a cover, a tape, pad, tool or mask 202 to create the stress profile heterogeneities that can withstand high temperature and do not contaminate the salt bath.

In one additional embodiment, a method to form weakened areas in a volume of a material would be to create a difference in the stress map at the surface of the material by thermal tempering. Internal stresses can also be originated form thermal tempering the hard layer if the material has a coefficient of thermal expansion sufficient enough (it is very difficult to temper silica glass for example). Here, by cooling the hot surface at a different rate, such a stress map, following the desired pattern 111 could be created. Different methods to generate a stress map can be performed. For instance, blowing air on the glass in a non-uniform way, or using Tool or mask 202 to create the stress profile heterogeneities such as a cold metal mask of the desired pattern 111 to cool the glass faster by putting it in contact with this mask.

Example 1: FIG. 7 illustrates a composite of 300*300*82.41 mm³ which use a strike face layer 100 made of a soda-lime glass having a thickness of 12 mm. The outer surface of the strike-face layer 100 has been slightly scratched along the pattern 111. The scratches 210 have been made by a diamond cutting scratching tool 201 with an applied force of 20 N and a speed of displacement of 10 mm/s. Intermediate layers 101 are made of soda-lime glass and have a thickness of 10 mm. Backing plastic layer 120 is made of a polycarbonate material and has a thickness of 6 mm. All layers (strike-face layer 100, intermediate layers 101, and backing layer 120) are bonded together by 0.63 mm thick adhesive materials 130, which are polyurethane interlayers. The thickness of the composition is 82.41 mm. The composition complies with STANAG 4569 L3 standard for KE ammunitions.

Example 2:

FIG. 8 illustrates a composite of 300*300*59.78 mm³ which use a 4 mm thick strike face layer 100 of Aluminosilicate glass. A first intermediate layer 101 is a 10 mm thick soda-lime glass. This an intermediate layer 101 has been processed by a laser 203 in order to create a 50*50 mm² grid of weaknesses. The laser 203 has been used to create 5-20 μπι defects 230 within the layer, along with this pattern 111. Defects 230 are separated by 100 μπι from one another. A second intermediate layer 101 is made of a soda-lime glass which has been submitted to a chemical strengthening. The resulting compressive stress is 550 MPa and the depth-of-layer is 22 μπι, the intermediate layer 101 is 10 mm thick. Following, there are two more intermediate layers 101 made of soda-lime glass of 10 mm thickness. The backing plastic layer 120 is made of PMMA and has a thickness of 12 mm. Each layer is bonded together by a 0.63 mm PU interlayer, with the exception of the backing plastic layer 120 which is bonded to the ultimate glass layer by 2 0.63 mm PU interlayers. The described composite complies with requirements set forth in EN 1063 BR7 at room temperature.

The above comprises a complete and detailed disclosure of several embodiments of the inventive concept herein claimed. Any skilled person in the art shall understand that variations may exist without falling away from the scope and spirit of the invention. The inventive concept claimed herein is only defined by the scope of the following claims, which shall be interpreted according to what was disclosed in the detailed description.

Claims

1. An armored glass composition with multi-hit performance, comprising:

a. a strike face layer;

b. at least one intermediate layer bonded to the strike face layer by an adhesive material;

c. one or more backing plastic layers, wherein one backing plastic layer is bonded to an intermediate layer by an adhesive material;

wherein at least one of either the strike-face layer or the intermediate layers have a weakened area.

2. The composition of Claim 1, wherein the weakened area is a tile-like formation applied with different forms and shapes.

3. The composition of Claim 1, wherein any of the strike-face layer or the at least one intermediate layer are comprised of materials selected from the group consisting of glass, glass-ceramic or transparent ceramic.

4. The composition of Claim 1, wherein a hard material layer serving as a protecting layer is bonded to the strike-face layer by an adhesive material.

5. The composition of Claim 1, wherein the weakened area is located in the strike-face layer.

6. The composition of Claim 1, wherein the weakened area is a scratched pattern having a scratching depth from 5 μπι to 1 mm.

7. The composition of Claim 1, wherein the weakened area comprises any patterned geometry.

8. The composition of Claim 7, wherein the patterned geometry corresponds to 6-edges hexagons or regular square-grid pattern.

9. The composition of Claim 1, wherein the weakened area corresponds to a second material embedded within the volume of a first material, wherein the first material is the material of the at least one of either the strike-face layer or the intermediate layers having the weakened area.

10. A method for providing weakened areas to a glass layer, the method comprising: a. providing a glass layer;

b. forming the weakened area over the surface of the glass layer by a process selected from the group consisting of:

i. inducing internal stresses in a pattern over or within the glass;

ii. thermal tempering;

iii. ion exchanging;

iv. scratching;

v. introducing defects within the glass by laser (scribing, cutting or engraving);

vi. creating an interface with another material by pressure and temperature; or

vii. by phase separation; and combinations thereof.

11. The method of claim 10, wherein the glass layer with weakened areas can be arranged with additional layers to form a glass composition.

12. The method of Claim 10, wherein the weakened is formed scratching the glass with a tool selected from the group consisting of indenter, blade, any cutting tool, or any automatic tool with any of a 2D or 3D cutting process, scattering (CNC), and combinations thereof.

13. The method of Claim 10, further including a step c) of polishing the glass chemically or mechanically.

14. The method of Claim 10, wherein the weakened is formed by creating an interface with a second material by pulverizing/spraying with high temperature and/or pressure such second material to allow penetration within the first material.

15. The method of Claim 10, wherein the weakened is formed by including extended fibers by stretching and pushing them into the material selected to be weakened.

16. The method of Claim 10, wherein the weakened area is formed by performing an ion exchange process to certain areas of the selected layer to be weakened.