WO2008112090A1

WO2008112090A1 - Projectile resistant composite structures and methods for making same

Info

Publication number: WO2008112090A1
Application number: PCT/US2008/002760
Authority: WO
Inventors: Norman Andreasen; John L. De Cristofaro; John Anthony Dispenza; Leon Klafter; Richard Thomas La Grotta
Original assignee: Lucent Technologies Inc.
Priority date: 2007-03-14
Filing date: 2008-02-29
Publication date: 2008-09-18

Abstract

The present techniques provide a number of composite structures that are resistant to penetration by projectiles. These structures include ceramic plastic composite panels, fiber plastic composite panels, and combined structures containing layers of both types of panels. The panels may be metal coated or jacketed for increased resistance. Such panels may be used in personal protection, vehicular protection, protection of space vehicles, or equipment protection.

Description

Projectile Resistant Composite Structures and Methods for Making

Same

By:

John L. DeCristofaro

Norman Andreasen

John Anthony Dispenza

Leon Klafter Richard Thomas LaGrotta

Projectile Resistant Composite Structures and Methods for Making Same

BACKGROUND OF THE INVENTION

Field Of The Invention

The present techniques relate to armor protective systems for projectile resistant applications. Specifically, the armor protective systems are made from panels that contain layers of a ceramic plastic composite material, a fiber plastic composite material, or both.

Description Of The Related Art

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

Protection from high velocity projectiles is a critical need in both law enforcement and military situations. This protection may take the form of armor plates, which may be used in two primary applications. The first is in protective body armor for personal protection from projectiles, while the second is in vehicles to prevent projectiles from penetrating the walls of the vehicle and injuring the occupants or damaging the contents.

Personal protective armor, such as bullet resistant vests and body armor, may take several forms. Perhaps the most widely used type comprises bullet resistant vests made from extremely high tensile strength plastic fibers, such as polyarimids or polyoxazoles. The fibers are tightly woven to make a fabric, then multiple layers are sewn together to make the vest. When the projectile hits the fabric, numerous fibers in successive layers break as the projectile penetrates, dispersing the energy of the projectile and bringing it to a stop before it can penetrate all of the layers. While this may prevent the projectile from actually penetrating the body of the person wearing the vest, it may not stop injury from the impact. To protect against injury from impact, vest makers often include plates over the front of the chest and back, often called trauma plates, which may distribute the impact over a wider area.

Many of the same issues are present in armor used for vehicular protection. Much of the vehicular armor used in ground based vehicles is made from metal plate. While metal plates may be very effective in deflecting or preventing the penetration of projectiles, they may also add significant weight to the vehicle. This increased weight may decrease the effective range of the vehicle and increase the costs of operation, which may lead to lower use of armor. Other types of vehicles, such as aircraft and water born vehicles, may also use armor, and weight issues may be even more significant for these types of craft.

Both for personal protection, and for vehicular armor, it is important to rate the ability of the armor to stop a projectile. The Department of Justice has created a rating system to identify the level of protection that personal armor systems may provide. This rating system, designated National Institute of Justice (NIJ) standard 0101.04, identifies five levels of protection based on the velocity and weight of the impact threat. For example, ballistic resistant body armor suitable for full time wear throughout an entire shift of duty for a police officer is available in classification Types I, HA, II, and IIIA, which provide increasing levels of protection from handgun threats. Type I body armor is the minimum level of protection that any police officer should have. Officers seeking protection from lower velocity 9 mm and 40 S&W ammunition typically wear Type IIA body armor. For protection against high velocity 357 Magnum and higher velocity 9 mm ammunition, officers traditionally select Type II body armor. Type IIIA body armor provides the highest level of protection available in concealable body armor and provides protection from high velocity 9 mm and 44 Magnum ammunition. Still higher levels are available for protection from high powered rifle rounds. These types of armor, type III and type IV, are intended for use only in short term tactical situations when the threat warrants such protection.

Classifying the type of an armor involves measuring the number of shots that 5 the armor can withstand from a particular caliber of weapon. For example, a type I armor must be able to withstand at least four hits, at a 0° incidence angle, from either a .22 caliber long rifle or a .38 caliber handgun, without penetration. Type IIA armor must be able to withstand at least four hits from either a low velocity 9 mm handgun or a .40 caliber Smith and Wesson handgun. Type II armor must withstand must be

_L0 able to withstand at least four hits from either a high velocity 9 mm handgun or a .357 magnum handgun. Type IIIA armor must be able to withstand at least four hits from either a high velocity 9 mm handgun or a .44 magnum handgun. The higher types, type III and type IV, are armor plates used for protection from high velocity rifle rounds. Type III must be able to withstand at least 6 hits from a 7.62 mm NATO rifle 5 (US M80 or .308 rifle), and a type IV must be able to withstand at least one hit by a .30 caliber armor piercing round.

Currently, most armor that may successfully protect against threats of type III and type IV is made from single ceramic plates. These ceramic plates may have the0 ability to stop very high velocity impacts, but may not be able to take more impacts than the minimum listed above without shattering. Once the plate has shattered, further shots may cause injury to the officer. Furthermore, ceramic plates may be very expensive to manufacture, which may limit their use to the military and larger police departments. Lower cost plates may be made from metal, but these may be quite heavy,5 weighing two to three times as much as ceramic plates giving equivalent protection.

Accordingly, research efforts are continuing to develop light, low cost armor panels that are resistant to multiple impacts and easy to manufacture. An armor of this type may be used both for personal protective use, and in thicker form, for use in0 vehicular applications. SUMMARY OF THE INVENTION

Certain aspects commensurate in scope with the originally claimed invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.

An embodiment of the present techniques provides a projectile resistant layered structure having at least one layer made from a blend of ceramic particles and a plastic matrix material, and at least one layer made from fibers embedded in a second plastic matrix material. The ceramic particles comprise at least 50% by volume of the blend.

Another embodiment provides a method for making protective armor. The method comprises blending ceramic particles into a plastic matrix material, wherein the ceramic particles comprise at least 50% by volume of the blend. A projectile resistant layered structure is made comprising one or more layers of the blend. In another aspect, the method comprises making one or more second layers having fibers in a second plastic matrix material. The second plastic matrix material may be the same or different from the first plastic matrix material. In this aspect, the second layers are disposed adjacent to the one or more first layers to form a panel.

Another embodiment provides an armor protected vehicle, wherein the armor comprises at least one first layer comprising a blend of ceramic particles and a plastic matrix material. The ceramic particles comprise at least 50% by volume of the blend. In another aspect, the armor comprises at least one second layer comprising fibers embedded in a second plastic matrix material.

Another embodiment provides a vest for protection from projectiles comprising at least one armor panel. The armor panel comprises at least one first layer having a blend of ceramic particles in a first plastic matrix material. The ceramic particles comprise at least 50% by volume of the blend.

BRIEF DESCRIPTION OF THE DRAWINGS Advantages of the invention may become apparent upon reading the following detailed description and upon reference to the drawings in which:

Fig. 1 is a perspective drawing of an exemplary embodiment of the present techniques, showing ceramic particles embedded in a plastic matrix;

Fig. 2 is a is a perspective drawing of another exemplary embodiment of the present techniques, showing a multilayer structure, in which layers containing ceramic particles embedded in a plastic matrix are joined to layers containing fibers in a plastic matrix;

Fig. 3 is a cross section of a multilayer structure, in accordance with embodiments of the present invention, showing the structure after multiple projectile impacts;

Fig. 4 is a perspective drawing of a ceramic plastic composite, shown by a cutaway view, disposed in a metal jacket or coating in accordance with embodiments of the current techniques;

Fig. 5 is a front view of a bullet resistant vest containing projectile resistant plates in accordance with embodiments of the current invention;

Fig. 6 is a front view of body armor containing projectile resistant plates in accordance with embodiments of the current invention;

Fig. 7 is a perspective view of a truck containing projectile resistant plates in accordance with embodiments of the current invention; Fig. 8 is a side view of a watercraft containing projectile resistant plates in accordance with embodiments of the current invention;

Fig. 9 is a front view of a helicopter containing projectile resistant plates in accordance with embodiments of the current invention;

Fig. 10 is a perspective view of a satellite containing projectile resistant plates in accordance with embodiments of the current invention; and

Fig. 11 is a perspective view of a cell phone antenna system with a housing containing projectile resistant plates in accordance with embodiments of the current invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made to achieve the developers' specific goals, such as compliance with system- related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

The current techniques include methods for making light, highly impact resistant armor panels that may be used in a number of applications for protection from projectiles. As discussed in detail below, these panels may be formed from a plastic matrix containing a high percentage of ceramic particles. The panels may be used individually for protection from lower level threats, or they may be combined with one or more layers that contain fibers in a thermoplastic matrix to protect from higher level threats.

For example, multilayer structures made from layers containing fibers in a thermoplastic matrix may be useful for protection from type IIIA, or lower, threats. In contrast, multilayer panels made from layers containing ceramic particles combined with other layers containing fibers in a thermoplastic matrix may be useful for type III threats. Indeed, these panels may be capable of withstanding more than 20 projectiles shot from a 7.62 mm (.308 rifle). Panels made from these composites may be used in body armor, or they may be formed into armor panels for wheeled vehicles, aircraft, or watercraft.

PLASTIC CERAMIC COMPOSITE

A ceramic plastic composite panel 10 that may be made in accordance with the present techniques is shown in Fig. 1. The ceramic plastic composite panel 10 may be made from a plastic matrix material 12 in which ceramic particles 14 have been embedded. The ceramic particles 14 may comprise at least 50% by volume of the ceramic plastic composite panel 10 and may comprise as much as 90 % of the ceramic plastic composite panel 10.

The plastic matrix material 12 selected to form the armored panel 10 depends on the performance characteristics desired. For example, the plastic matrix material 12 may either be a thermoplastic or a thermoset depending on the moldability, recycling, or other functional characteristics. Thermoplastics that may be used in embodiments of the present techniques, include, by way of example, polycarbonate, polyphenylene sulfide (PPS), poly(ether ether ketone) (PEEK), styrene butadiene copolymers, acrylonitrile butadiene styrene (ABS) copolymers, polyurethanes, polyamides, or various combinations thereof, depending on the performance properties needed.

Alternatively, if the application does not require any possibility of recycling or reuse of the plastics, a thermoset plastic may be used for the plastic matrix material 12. Thermoset materials that may be used in embodiments of the present techniques include, by way of example, epoxy resins, vulcanized rubber, polyurethanes, polyamides, or combinations thereof, depending on the properties needed.

Furthermore, any number of additives may be blended into the plastic matrix material 12 to improve the performance of the ceramic plastic composite panel 10. Additives that may be used include stabilizers and flow enhancers, among others. For example, stabilizers may be added to improve the oxidative resistance of the ceramic plastic composite panel 10, which may increase the useful lifespan of the armor. Such stabilizers may include hindered phenolic stabilizers, such as Irganox 1010 or Irganox 1076, available from CIBA Corporation, among others. Other oxidative stabilizers may be added, including such stabilizers as tris-nonyl phenol phosphite (TNPP), other phosphites, or cyclic lactides, among others. Further, flow agents may be added to the plastic matrix material 12 to improve the wetting of the ceramic particles 14. Improved wetting of the ceramic particle 14 may reduce the formation of voids, resulting in improvements in the performance of the ceramic plastic composite panel 10. For example, polycarbonate may have a very high melt viscosity, resulting in poor flow around the ceramic particles 14. Lower viscosity resins may be used, but these may have lower impact strength. The addition of a macrocyclic poly (butylene terephthalate) (PBT), available as CBT ^® from Cyclics^® Corporation, may lower the melt viscosity, which may lead to lowering the number of voids formed in the matrix.

In addition to the plastic matrix material 12, the other major components of the ceramic plastic composite armor plate 10 are the ceramic particles 14. The ceramic particles 14 may be selected from ceramic materials, including, by way of example, alumina, boron carbide, boron nitride, silicone carbide, silicone nitride, magnesium silicate, magnesium oxide, titanium carbide, titanium oxide, tungsten carbine, zirconia, or combinations of these materials. The selection of the material may be made on the basis of factors such as the threat protection needed and the overall cost of the structure. For example, alumina particles may provide the lowest overall cost, but harder materials, such as boron carbide, may provide more effective protection in thinner structures.

The size of ceramic particles 14 may range from greater than 100 micrometers to less than 10,000 micrometers. A wide particle size distribution may improve the performance of the panel in two ways. While larger particles may be more effective at stopping projectiles, smaller particles may improve the packing efficiency in the matrix. Improved packing of the ceramic particles 14 may lead to a higher concentration of ceramic particles 14 in the plastic matrix material 12. This higher concentration will increase the number of particles a projectile encounters upon impact, increasing the chances of fragmenting and slowing the projectile. Furthermore, improved packing may place more ceramic particles 14 in direct contact with each other, which may distribute the force of the impact over a wider area.

In embodiments of the present technique, the ceramic particles 14 may comprise shapes ranging from spheres to random rough fragments. In one embodiment, the ceramic particles 14 may comprise flat particles, which may be aligned with the flat surfaces parallel to each other and to the impact surface of the ceramic plastic composite panel 10. Alignment of flat ceramic particles 14 may be achieved by taking advantage of the shear force from polymer flow during the molding process to align the particles. The use of flat particles may increase the surface area of the ceramic particles 14 encountered by a projectile upon impact. This may provide a further advantage over round or rough ceramic particles 14 by distributing the force over a wider area. Furthermore, the use of flat particles may increase the number of particles that a projectile will need to shatter to penetrate the armor, versus ceramic particles 14 that may be pushed aside by a projectile.

The ceramic plastic composite panel 10 described above may be used for lower impact threats such as a stand alone plate in a bullet resistant vest. For example, the ceramic plastic composite panel 10 may be used in applications where the plate distributes the impact of a hit over a vital region, and the vest improves the resistance of the structure to penetration by a projectile. Still higher penetration protection may be achieved by joining layers of the ceramic plastic composite panel 10 with other layers, as described below.

LAYERED ARMOR PANELS

An example of a multilayered armor panel 22 may be seen in Fig. 2. hi Fig. 2, a ceramic plastic composite panel 10 containing ceramic particles 14 may be attached to a fiber plastic composite panel 16. The fiber plastic composite panel 16 may be made from a second plastic matrix material 18 containing embedded fibers 20. The resulting multilayered armor panel 22 may be comprised of one or more layers of the ceramic plastic composite panel 10 combined with one or more layers of the fiber plastic composite panel 16. The layers do not have to be sequential, e.g., with the ceramic plastic composite panel 10 on one side and the fiber plastic composite panel 16 on the other side, but may have different layers having different compositions interspersed therein, as described with respect to the examples. The second plastic matrix material 18 may be the same as the first plastic matrix material 12, or a different material may be selected. Selection of the second plastic matrix material 18 is performed as described above for the ceramic plastic composite panel 10, and the same materials may be used.

The fibers 20 used to form the fiber plastic composite panel 16 may be made from any sufficiently strong material, including: glass; metal; polyamides; polyaramides, such as Kevlar^®, available from DuPont, or Dyneema^®, available from DSM; carbon fibers; polyolefins, such as Spectra^®, available from Honeywell; polyurethanes; polyamide copolymers; poly(p-phenylene-2,6-benzobisoxazole), available as Zylon from Toyobo; or combinations thereof. If the fibers 20 are made from metal, a number of metals may be chosen, including titanium, steel, or any other metal that may be used to form a fiber with the appropriate weight and strength characteristics. Such alternate metals may include manganese alloys, among others. The choice of the fibers 20 may depend on the performance and cost desired. For example, a fiber plastic composite panel 16 made using fibers 20 comprising a titanium mesh may provide high protection in a thinner multilayered armor panel 22, but may not be as cost effective as other choices used to make a thicker multilayered armor panel 22 giving the same protection.

The fibers 20 may be embedded in the second plastic matrix material 18 as a woven mesh or alternatively, may be used a non-woven fabric material. The choice of a woven fiber mesh or a non-woven fabric will depend on the strength and properties of the fiber plastic composite panel 16 desired. Glass fibers 20 woven into a mesh were used in exemplary embodiments of the fiber plastic composite panel 16.

As discussed above for the ceramic plastic composite panel 10, the fiber plastic composite panel 16 may be used by itself for lower threat levels. If higher threat protection is needed, a final multilayered armor panel 22 can be assembled by pressing together one or more layers of a ceramic plastic composite panel 10 with one or more layers of a fiber plastic composite panel 16, using layers of thermoplastic to hold the panels together. This may be performed by placing the individual panels into a hot mold with layers of thermoplastic separating the layers. The mold is closed under high pressure, melting the thermoplastic between the layers, forming a multilayered armor panel 22. Alternatively, a multilayered armor panel 22 may be formed by either bonding the individual panels together with an adhesive, or by physically holding the panels together with a frame. Both the fiber plastic composite panel 16 and the multilayered armor panels 22 may be highly resistant to impact, as discussed for the examples below.

EXAMPLES OF FIBER PLASTIC COMPOSITE PANELS

Without intending to be limiting, the formation conditions used to make several exemplary fiber plastic composite panels 16 are shown in Table 1 below. All of the fiber plastic composite panels 16 were made from six to ten layers of type S2 fiber glass, using Lexan^® EXL 9330 high impact polycarbonate, from GE Plastics, as the second matrix material 18. The raw materials were layered in a press and held at a pressure of 3 tons, while being heated to 500⁰F for varying periods of time, as shown under "Heat Up Time" in Table 1. After the materials had been heated for the time selected, the pressure was increased to the forming pressures shown and held for 15 minutes. After forming, the samples were allowed to cool to the temperatures selected, while being held under the pressures shown. After forming, the fiber plastic composite panels 16 weighed from 2.3 to 4.5 pounds, and were from 0.26 to 0.50 inches thick. The fiber plastic composite panels 16 were tested using 9 mm and 0.440 magnum handguns, similar to the NIJ requirements for Type IIIA body armor. As shown in Table I, the majority of these structures were able to stop these projectiles.

TABLE 1 : Exemplary Fiber Plastic Composite Panels

Number Heat Up Forming Cooling Actual Panel 4

OdiTI. Cooling Q 4 y M_n of Fiber Time P. T (OE\ P. molded Thick. Mag

INO. I ( r ) mm

Layers (min.) (Tons) (tons) wt (lbs) (in.) SWC

1 6 12.0 30 260 45 2.3 0.26 Pass n/a

2 10 6.0 30 260 45 3.8 0.41 Pass n/a

3 10 12.0 30 260 45 3.7 0.40 Pass n/a

4 10 12.0 30 260 45 4.5 0.50 Pass Pass

5 10 12.0 30 70 30 4.4 0.51 Pass Pass

6 6 12.0 30 280 30 2.3 0.29 Pass Fail

7 8 15.0 60 280 60 3.6 0.40 Pass Pass

8 6 15.0 75 280 75 2.7 0.28 Pass Pass

9 8 12.0 25 230 25 3.0 0.33 Pass Fail

10 8 12.0 25 230 25 3.2 0.34 Pass Pass

11 8 12.0 25 230 25 3.3 0.38 Pass Pass

12 8 12.0 50 230 25 3.1 0.36 Pass Pass

EXAMPLE OF MULTILA YERED ARMOR PANEL

To test if higher protection levels could be achieved, an exemplary multilayered armor panel 22 was made using the techniques discussed above. The materials and conditions that were used are shown below in Table 2. In this example, a strike face was prepared from a ceramic plastic composite panel 10 with a fiber plastic composite panel 16 on each of the front and the back surfaces. This structure was molded to a structure comprising multiple layers of fiber plastic composite panels 16. For both the ceramic plastic composite panel 10 and the fiber plastic composite panels 16 the plastic matrix material 12,18 was Lexan EXL 9330 high impact polycarbonate with CBT added to enhance the flow properties, as discussed above. The multilayered armor panel 22 was tested using a 7.62 millimeter (.308 caliber) rifle and withstood 23 shots without penetration. By comparison, the NIJ standard for a Type III armor panel requires that the panel withstand only at least 6 shots from a rifle of this caliber.

TABLE 2: Conditions for forming an exemplary multilayered armor panel

Ceramic plastic composite panel

Fiber layers front and back

Lexan 9330 polycarbonate w/CBT front and back

BAO #6 grains 6.4 lbs Prep - Washed and Dried

Lexan 9330 polycarbonate w/CBT mixed with Grains

Molded at 500 F for 30 min.

Panel : 9.16 1b x .78 thick

Fiber plastic composite panel

Fiber squares, 18pcs

Lexan 9330 polycarbonate w/CBT, 19 layers

Molded at 500 F for 30 min.

Panel: 8.86 Ib x 1.135" thick

Multilayered armor panel

Individual panels molded together at 500⁰F for 45 min. Additional polycarbonate used for re-mold = ,41b

It is believed that the mechanism that gives the multilayered armor panel 22 the ability to resist multiple, high-velocity impacts is based on the different composition of each of the individual layers. The first layer, made from the ceramic plastic composite panel 10, may fragment a projectile, wherein the second layers, made from the fiber plastic composite panels 16, may capture the fragments, stopping them before they reach the wearer.

The results of impact events may be seen more clearly in Fig. 3, which shows a cross-section view of a panel that has taken multiple strikes. As shown in Fig. 3, the ceramic plastic composite panel 10 is attached to a fiber plastic composite panel 16 containing multiple fiber layers. Layers of the fiber plastic composite panels 16 may also be deposited on top of the ceramic plastic composite panel 10 to prevent fragments of the projectile or ceramic grains from exploding back out of the armor panel and harming either the wearer or other nearby persons. Upon impact, a projectile 24 may be fragmented by the ceramic particles 14. The projectile fragments 26 proceed through the ceramic plastic composite panel 10, impacting more ceramic particles 14 and being further decelerated. The fragments 26 may then be captured by the fiber plastic composite panel 16. Multiple impact sites 28 and 30 may be very close to each other without penetration of the multilayered armor panel 22. As the unit is not a single integral structure, in contrast to the ceramic plates in current use, each projectile impact 28 and 30 may destroy the ceramic particles 14 and tear the fiber matrix 20 in a small area around the impact site, without affecting ceramic particles 14 or the fiber matrix 20 at a farther distance.

METAL ENCASED ARMORPANELS

Another technique that may be used in embodiments of the present techniques to improve the impact resistance of any of the panels described above is shown in Fig. 4. In this figure, a ceramic plastic composite panel 10 made up of the matrix material 12 and embedded ceramic particles 14 may be encased in a metal jacket or coating 28 to form a metal encased armor panel 29. To form the metal encased armor panel 29, a metal coating 28 may be applied by depositing metal onto the surface of the ceramic plastic composite panel 10, using metal vapor deposition techniques for example. Alternatively, the ceramic plastic composite panel 10 may be molded into a metal case 28 which may then be welded shut. This technique may also be used to improve the impact resistance of a fiber plastic composite panel 16 or a multilayered armor panel 22.

In addition to providing a further barrier to an impact, the metal encased armor panel 29 may have improved impact resistance from the hoop stress of the metal coating or jacket 28 around the outer edge. For example, in order to penetrate the metal encased armor panel 29, an incoming projectile would be required to penetrate the metal coating or jacket 28 and force the plastic matrix 12 and the ceramic particles 14 or fibers 20 aside, which may force the metal encased armor panel 29 to burst at the sides. The pressure required to burst the metal sides may add further force protection to the panel. Depending on the metal coating technique used and the thickness of the metal layers, a metal encased armor panel 29 may be lighter, for a given protection level, then other types of armor.

APPLICATIONS OF PLASTIC COMPOSITE ARMOR PANELS The armor panels discussed above, hereby collectively referred to as projectile resistant plates 30, may be used in both personal protective applications, as shown in Figs. 5 and 6, and vehicular applications, as shown in Figs. 7, 8, and 9. Further, the projectile resistant plates 30 may also be used in other, more exotic applications such as in satellite housings, as shown in Fig. 10. Alternatively, the relatively low cost of the projectile resistant plates 30 may allow their use in lower value applications, as shown in Fig. 1 1.

An example of an embodiment using projectile resistant plates 30 in accordance with embodiments of the current techniques is shown in Fig. 5. In this figure, a bullet resistant vest 32 contains front and back panels made from projectile resistant plates 30 to protect the wearer from impact damage to the chest or back. The bullet resistant vest 32 has fastening straps 34 made from hook and eye material to hold the bullet resistant vest 32 and projectile resistant plates 30 in place. Optionally, a protective collar 36 may also contain projectile resistant plates 30.

If more protection is needed than provided by a bullet resistant vest 32, full body armor 38 may be prepared, as shown in Fig. 6. In body armor, the projectile resistance plates 30 cover a greater area of the body than for the bullet resistant vest 32. The body armor has fastening straps 34 made from hook-eye material to hold the body armor 38 and projectile resistance plates 30 in place. An optional protective collar 36, containing projectile resistant plates 30, may be used. Greater protection than for bullet resistant vests 32 or body armor 38 may be obtained if from the user is traveling in a projectile resistant vehicle.

An example of a wheeled vehicle 40 protected by projectile resistance plates 30, in accordance with embodiments of the present techniques, is shown in Fig. 7. In this illustration, a number of projectile resistant plates 30 are shown protecting the doors, the roof, the fire wall, and in other positions around the passenger compartment 41 and engine compartment 42. In addition to post production mounting of projectile resistance plates 30 in a vehicle, the body parts may actually be formed from the projectile resistant plates 30, due to the moldability of the ceramic plastic composite panels 10 and the fiber plastic composite panels 16. Furthermore, the moldablity of the panels may make other applications possible. For example, tires 43 or engine hoses 44 may be made from layers containing projectile resistant composite materials in accordance with embodiments of the present techniques. The use of the projectile resistant plates 30 is not confined to personal protection or wheeled vehicles 40.

As shown by Fig. 8, embodiments of the present technique may also be used to protect water-borne vehicles as well. In Fig. 8, a fast attack vessel 46 has projectile resistant plates 30 protecting the passenger cabin 47 and the hull 48 of the craft. As discussed above, the moldability of the materials makes it possible to either mount projectile resistant plates 30 in existing water-borne, or form the hull, and other parts, of the water-borne vehicles from the projectile resistant composite materials of the present techniques. With the protection provided by the projectile resistant plates 30 such a fast attack vessel 46 may be able to carry weapon systems 49 closer to a target. Further, the light weight of the projectile resistant plates 30 may improve the efficiency of the vessel, allowing longer range missions.

Other applications may also take advantage of the light weight of the projectile resistant plates 30. An example of a vehicle that may require light weight armor is shown in Fig. 9, which illustrates a helicopter 50 that may contain parts protected by or formed from projectile resistant plates 30 in accordance with embodiments of the present invention. The helicopter 50 is powered by engines 52 that provide lift through the blades 54 and power the stabilizing rotor 56. Projectile resistant plates 30 may be used around the pilot compartment 58 and the engines 52. The light weight and multiple impact resistance of the projectile resistant plates 30 of the present invention are significant benefits for this application. An even more weight sensitive application is show in Fig. 10, which illustrates a satellite 58. The satellite 58 has a housing 60 that holds an electronics package that is powered by solar cells 62 and communicates to the ground through an antenna 64. Because of the risk of damage from micrometeorites and other high speed projectiles in space, the housing 60 must be protected from impact. In this application, projectile resistant plates 30 in accordance with the present techniques may be used to prevent micrometeorites from penetrating the housing 60 and damaging the electronics.

Although the high performance of the projectile resistant plates 30 of the present techniques may make them appropriate for use in high value applications, such as those discussed above, the low cost of materials that may be selected may make the projectile resistant plates 30 practical for use in less critical applications. An example of such an application is shown in Fig. 11, which is a perspective view of a cellular phone antenna system 66. In this illustration, antennae 68 for communicating with cellular telephones are located at the top of a tower structure 70. An electronics housing 72 is located at the base of the tower structure 70. The housing 72 contains electronics to handle the connections between landlines 74 and the antennae 68. Although the tower structure 70 and electronics housing 72 are protected by a fence 76, this cannot protect the electronics from damage by gunshots. In an embodiment of the present technique, the electronics housing 72 may have projectile resistant plates 30 mounted on the exterior or interior surfaces to protect the electronics from such damage. Alternatively, the housing may be formed from the projectile resistant plates 30 of the current techniques.

It should be understood that the present techniques have been described above by way of example and that such techniques may apply in other situations as well. Indeed, the present techniques may prove useful in situations other than protecting persons and structures from projectiles. For instance, the projectile resistant plates 30 of the present techniques may be useful for other types of personal protective equipment, such as bomb disposal suits and battle helmets, wherein the light weight may improve the utility of the items. The projectile resistant composite panels detailed herein may also be useful in chemical, fuel, and ammunition storage to protect containers from intentional or unintentional projectiles. Further, the low cost of such projectile resistant composite panels may make the use of ballistic protection practical for situations where a ballistic threat is improbable, but of high consequence. For example, the projectile resistant plates 30 of the present techniques may be used in and between small shops in geographic locations where terrorist attacks are more likely to occur.

While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and/or described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

CLAIMSWe claim:

1. A projectile resistant layered structure comprising at least one first layer comprising a blend of ceramic particles and a first plastic matrix material, wherein the ceramic particles comprise at least 50% by volume of the blend; and at least one second layer comprising fibers embedded in a second plastic matrix material.

2. The projectile resistant layered structure of claim 1 wherein at least one of the first or the second plastic matrix material comprises a thermoplastic material comprising at least one of a polycarbonate, a poly(phenylene sulfide), a poly(ether ether ketone), a styrene butadiene copolymer, an acrylonitrile-butadiene-styrene (ABS) copolymer, a polyurethane, a polyamide, or any combination thereof.

3. The projectile resistant layered structure of claim 2 wherein at least one of the first or the second plastic matrix material comprises a thermoset material comprising at least one of an epoxy, a vulcanized rubber, a polyurethane, a liquid crystalline polymer, a polyamide, or any combination thereof.

4. The projectile resistant layered structure of claim 1 wherein the ceramic particles comprise at least one of alumina, boron carbide, boron nitride, silicon carbide, silicon nitride, magnesium silicate, magnesium oxide, titanium carbide, titanium oxide, tungsten carbide, zirconia, or any combination thereof.

5. The projectile resistant layered structure of claim 1 wherein the fibers are comprised of at least one of a glass, a metal, a polyamide, a polyaramid, carbon, a polyolefin, a polyurethane, a polyamide copolymer, poly(p-phenylene-2,6- benzobisoxazole), or any combination thereof.

6. The projectile resistant layered structure of claim 1 comprising a metal disposed over the structure.

7. A method for making protective armor comprising: blending ceramic particles into a plastic matrix material, wherein the ceramic particles comprise at least 50% by volume of the blend; and making a projectile resistant layered structure, wherein the blend comprises one or more layers in the structure.

8. The method of claim 7 comprising: making one or more second layers comprising fibers in a second plastic matrix material, wherein the second plastic matrix material may be the same or different from the first plastic matrix material; and disposing the one or more second layers adjacent to the one or more first layers to form a panel.

9. The method of claim 7 comprising depositing a metal coating over the protective armor.

10. The method of claim 7 comprising molding the protective armor in a metal encasement.