US20110162516A1

US20110162516A1 - Method of Layering Composite Sheets to Improve Armor Capabilities

Info

Publication number: US20110162516A1
Application number: US12/652,587
Authority: US
Inventors: Alexander F. St. Claire; Timothy J. Imholt; Michael Noland
Original assignee: Raytheon Co
Current assignee: Raytheon Co
Priority date: 2010-01-05
Filing date: 2010-01-05
Publication date: 2011-07-07

Abstract

According to one embodiment, an armor system comprises a plurality of polylithic composite armor panels. Each of the polylithic composite armor panels comprising a plurality of layers. The plurality of layers comprise at least two layers having a different Young's modulus. Each of the plurality of layers comprising a plurality of sheets. The plurality of sheets comprise one or more fibers. The plurality of sheets have one or more respective weave characteristics.

Description

TECHNICAL FIELD

This invention relates generally to the field of armor systems and more particular to a layering of composite sheets to improve armor protection.

BACKGROUND

Shape charges such as Explosively Formed Penetrators (EFPs) have accounted for a large number of combat casualties. Lethality of EFPs comes in part from the shape and arrangement of a concave copper cone, called the liner, which transforms into a forceful jet of fluidic metal which easily perforates armor. Despite focused efforts on armor development, Mine Resistant Ambush Protected (MRAP) vehicles and other armored vehicles still cannot defend against these threats. More recently, armor solutions such as the FRAG Kit 5 have been used to protect military vehicles such as Humvees. However, these armor solutions typically weigh around 200 lb/ft². Since nearly all army vehicles are thousands of pounds overweight, even without any additional armor protection solution, most of these approaches have proved impractical.

SUMMARY OF THE DISCLOSURE

According to one embodiment, an armor system comprises a plurality of polylithic composite armor panels. Each of the polylithic composite armor panels comprising a plurality of layers. The plurality of layers comprise at least two layers having a different Young's modulus. Each of the plurality of layers comprising a plurality of sheets. The plurality of sheets comprise one or more fibers. The plurality of sheets have one or more respective weave characteristics.
The sheets and layers may be held together by at least one adhesive agent. In some embodiments an adhesive may comprise a resin. In some embodiments, a sheet and/or a layer and/or an entire composite panel may have a considerable variation in resin concentration as compared to another sheet and/or another layer and/or another composite panel. In some embodiments, low resin concentrations may be used.
In some embodiments, composite panels may be polylithic composite panels. In some embodiments, composite panels may be monolithic composite panels.
Some of the embodiments, as set forth above, have similar features for both monolithic and/or polylithic panels. In some example embodiments, a sheet comprised in a polylithic and/or a monolithic panel may comprise one or more fiber characteristics such as but not limited to fiber types (i.e., fibers made of different materials) and/or different fiber thickness.
However, according to some embodiments, a sheet comprised in a polylithic may have more than one weave characteristics and comprises at least two or more directions of weave of fibers in a panel. In contrast, in some embodiments, a monolithic panel may have one or more weave characteristics of fibers in a panel, with the exception, of direction of weave. Accordingly, in some embodiments, monolithic panels may have a uniform direction of weave of fibers in one panel. For example, a monolithic panel may have only one direction of weave of fibers in a panel.
Embodiments relating to weave characteristics and/or fiber characteristics are described in further detail later in the specification.
Some embodiments of the disclosure relate to polylithic armor systems and polylithic armor panels. In certain embodiments, the disclosure describes an armor system comprising a plurality of polylithic composite panels having at least two layers having a different Young's modulus.
In some embodiments, an armor system may comprise at least one polylithic panel that comprise at least one layer comprised of thicker fibers located toward the front or outer side of the armor system and at least one layer comprised of finer fibers located toward the back or inner side of the armor system.
In some embodiments a polylithic panel may comprise at least two layers comprising sheets having a thicker weave on the top and a finer weave in back.
In some embodiments, a polylithic composite armor panel of an armor system may comprise at least two layers. In some embodiments, a polylithic composite armor panel of an armor system may comprise at least three layers.
Some embodiments of the disclosure relate to monolithic armor systems and monolithic armor panels. In some embodiments, an armor system may comprise at least a first monolithic composite armor panel comprising layers having a thicker and more flexible weave mesh, the first monolithic panel located toward the outer side of the armor system and at least a second monolithic composite armor panel comprising layers having a finer rigid weave mesh, the second monolithic panel located toward the inner side of the armor system.
According to some embodiments, an armor system may be comprised of layers of thin monolithic panels, the thin monolithic panels having a thickness of less than or equal to 0.5″.
Teachings of certain embodiments relate to designing armor solutions using polylithic armor panels and/or using monolithic armor panels, to protect vehicles and personnel from a variety of projectile devices including but not limited to shape charges, EFP's, IEDs, ballistic devices and hypervelocity impacts.
According to some embodiments, having a more flexible composite panel toward the outer side of an armor system may provide an ability to bend or flex backwards slightly following an impact thereby causing a longer dwell time. Increasing the impact time may advantageously decrease the amount of force exerted by a projectile upon an armor panel at any given point of time.
Flexibility of an armor panel may be controlled in part by the nature of fibers, thickness of fibers, directionality of weave and/or mesh size as described in certain embodiments. A very flexible panel may not be able to sustain a very larger impact force. Also over flexing may cause a deformation of the armor and injure occupants on the inner side. Accordingly, teachings recognize that a balance between hardness of a panel and flexibility of a panel may provide the best ballistic protection.
Certain embodiments recognize optimal use of delamination, i.e. peeling away of a sheet from an adjacent sheet, to dissipate energy of an incoming projectile. Teachings of certain embodiments recognize improving energy absorption of an armor system through physically breaking glass threads. For example, certain embodiments recognize that an armor system having sheets with a finer mesh has more bonds that must be broken. In another example, certain embodiments recognize that an armor system having sheets with more complex weave directionality (e.g., a [0°/+45°/−45°/90°]s weave), the presence of a larger number of angles in the sheets increase the energy absorbing capacity of the armor system.
Certain embodiments of the invention may provide one or more technical advantages. A technical advantage of one embodiment may include the capability to increase the dwell time of a projectile thereby reducing the force exerted force by a projectile device. A technical advantage of one embodiment may include the capability to change the trajectory of a projectile device. A technical advantage of one embodiment may also include the capability to increase impact time. A technical advantage of one embodiment may also include the capability to lowering the force exerted on one or more armor layers of an armor system. A technical advantage of one embodiment may also include the capability to decrease the overall impact of a projectile.
According to some embodiments, armor systems having layers of different composite panel compositions as set forth above may results in slowing the penetrating tip located on the front of an EFP such that rear portions (or particles) of the EFP re-collide with front portion. As rear EFP particles pushes forward on the front part the penetrating tip of an EFP gets pushed towards the sides and the front of the EFP becomes flattened. This significantly reduces the missile shape reformation ability of an EFP which is responsible for its superior penetrating ability. Accordingly, a technical advantage of one embodiment may also include the capability to decrease the shape change ability of a projectile.
Further technical advantages of particular embodiments of the present disclosure may include an armor system that is lighter weight than conventional armor. A lightweight armor system of the present disclosure may be capable of protecting against a similar threat as a heavier conventional armor system. Yet another technical advantage of one embodiment may be a relatively low cost solution to provide protection against a variety of projectiles and high velocity impacts. In particular, armor systems comprising polylithic composite panels or monolithic composite panels in accordance with the present disclosure may protect against an shape charge such as an EFP, other explosive devices such as IED's, other projectile threats, bullets, ballistic threats and/or forms of hypervelocity impact.
Various embodiments of the invention may include none, some, or all of the above technical advantages. One or more other technical advantages may be readily apparent to one skilled in the art from the figures, descriptions, and claims included herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1A shows an armor system having a plurality of polylithic composite armor panels, according to one example embodiment;

FIG. 1B shows a cross-section of one polylithic composite armor panel of FIG. 1A and depicts a plurality of layers comprised in one polylithic composite armor panel, according to one example embodiment;

FIG. 1C shows an enlarged view of one layer as shown in FIG. 1B and shows each layer further comprised of a plurality of sheets, according to one example embodiment;

FIG. 1D shows an enlarged cross-sectional view of a layer as shown in FIG. 1C depicting a plurality of sheets and showing a plurality of fibers comprised in the sheets, according to one example embodiment;

FIGS. 2A, 2B and 2C depict fineness of weaves of example sheets where FIG. 2A shows an example thick weave, FIG. 2B shows an example medium weave and FIG. 2C shows an example fine weave, according to one example embodiment;

FIG. 3A shows an enlarged view of an example polylithic panel having at least two layers, the top layer having thicker weaves and the bottom layer having finer weaves, according to one example embodiment;

FIG. 3B shows an enlarged view of an example polylithic panel having at least three layers, the top layer having thicker weaves, the middle layer having medium weaves and the bottom layer having finer weaves, according to one example embodiment;

FIG. 3C shows an enlarged cross-sectional view of an example polylithic panel having at least two layers, the top layer having sheets comprised of thicker fibers and the bottom layer having sheets comprised of finer fibers, according to one example embodiment;

FIG. 4 depicts an armor system having polylithic armor panel layers, wherein at least two layers have a different Young's modulus, according to one example embodiment;

FIG. 5A shows an armor system having a plurality of monolithic composite armor panels, according to one example embodiment;

FIG. 5B shows a cross-section of one monolithic composite armor panel of FIG. 5A and depicts a plurality of layers comprised in one monolithic composite armor panel, according to one example embodiment;

FIG. 5C shows an enlarged view of one layer as shown in FIG. 5B and shows each layer further comprised of a plurality of sheets, according to one example embodiment;

FIG. 5D shows an enlarged cross-sectional view of a layer of FIG. 5C showing a plurality of sheets and depicts each sheet comprised of a plurality of fibers, according to one example embodiment;

FIG. 6A shows an enlarged view of a monolithic panel having at least three layers comprising sheets having thicker flexible weaves, according to one example embodiment;

FIG. 6B shows an enlarged view of a monolithic panel having at least three layers comprising sheets having finer rigid weaves, according to one example embodiment;

FIG. 6C shows an enlarged cross-sectional view of an example monolithic armor system comprised of at least two monolithic panels, a first monolithic panels as in FIG. 6A located on the outer side of the armor system and a second monolithic panel as in FIG. 6B located on the inner side of the armor system, according to one example embodiment;

FIG. 7 depicts a vehicle comprising an armor system, polylithic or monolithic, of the disclosure, in accordance with one example embodiment;

FIGS. 8A and 8B show an exemplary path of an explosively formed penetrator (EFP) through a prior art armor system not having layered composites as taught in the present embodiments, wherein, FIG. 8A depicts an example shallow-disk shaped EFP making contact with a first layer of armor located on an outer side of the prior art armor system and FIG. 8B depicts the EFP now formed into a missile-shaped structure as it penetrates through layers of prior art armor; and

FIGS. 9A, 9B and 9C illustrate an exemplary path of an explosively formed penetrator (EFP) through one embodiment of a layered composite (monolithic or polylithic) armor system of the disclosure wherein FIG. 9A depicts an example shallow-disk shaped EFP contacting an outer side of the armor system; FIG. 9B depicts the EFP as it penetrates through a first layer of armor which flexes, slows the EFP, flattens the surface-tip of the EFP and its shape-change ability; and FIG. 9C illustrates the EFP as it penetrates through a second layer of armor which further flexes additionally slowing the impact, flattening the surface tip and reducing shape change ability of the EFP, according to one example embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

It should be understood at the outset that, although example implementations of embodiments of the invention are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or not. The present invention should in no way be limited to the example implementations, drawings, and techniques illustrated below. Additionally, the drawings are not necessarily drawn to scale. In some embodiments, like numbers in the drawings may refer to like parts.
Teachings of certain embodiments recognize that armor systems may be used to provide protection against and/or reduce impact of various projectiles such as but not limited to shaped charges, EFP's, IEDs, ballistic devices, other explosives and hypervelocity impacts. Armor systems of the disclosure may be used in conjunction with any vehicle, such as but not limited to, military vehicles, convoy vehicles and/or personnel carriers and may be useful to protect personnel and equipment in war zones.
On the battlefield, shape charges such as explosively formed penetrators (EFPs), also known as explosively formed projectiles, pose serious threat to equipment and personnel. EFPs and other shape charges may have the ability to pierce through the armor of a vehicle and injure or kill the occupants inside.
Various configurations of shape charges and EFPs have been developed and several are capable of penetrating extremely thick and heavy armor. Therefore, merely adding more armor layers to protect against a shape charge may result in a vehicle that is overweight and less effective on the battlefield. In accordance with a particular embodiment of the present disclosure, a lightweight armor system may be capable of stopping a projectile or significantly reducing its destructive capability.
While not wishing to be bound to any particular theory, the present section provides a brief description of how high energy explosives and shape charges may achieve their lethality. High explosives may be extremely powerful because of their ability to rapidly release energy in the form of heat and pressurized gas. The extremely fast rate at which this energy may be discharged gives a high explosive its strength. Rapid discharge of a large amount of energy into a small space may generate shock waves. For example, rapidly released energy may compress neighboring air or surrounding material that further increase its velocity. The compressed air may then rapidly propagate outward and create a shock wave.
When a high explosive is detonated, an explosion may begin at a small portion at the edge of the explosive. This explosion may create a shock wave that may propagate through the rest of the explosive. When this shock wave comes in contact with a portion of the high explosive that has not yet exploded the shock wave detonates the unexploded explosive. Thus, the additional explosion causes the shock wave to increase in velocity.
By exploiting the properties of a high explosive, in conjunction with certain geometric configurations, a more powerful and more focused blast may be accomplished. Shape charges utilize properties of high explosives and a conical geometric shape, lined with a metal liner, to achieve an explosion that can reshape material from the metal liner into a penetrating configuration at the same time accelerating it by a high energy explosion.
Inertial forces of a material (e.g., metal from a metal liner) that are being propelled by an explosion from rest to a hypervelocity may affect the molecular structure of the material. A hypervelocity may be a velocity of over 6,700 miles per hour. Acceleration from rest to a hypervelocity generates extremely high inertial forces. These inertial forces may be significantly greater than the molecular forces holding the particular material together. As a result, the material may change its form and may convert from a solid to a liquid with the dominating inertial forces guiding the flow of the material.
EFPs and other shape charges use these principles while unleashing their explosive power. A shaped charge may be able to pierce a thickness of steel armor equal to six-times its diameter.
When a shape charge is detonated a shock wave that detonates the charge reaches the tip of its metal liner. The liner tip may accelerate forward due to inertial forces and reach a hypervelocity changing the solid metal into a fluid. As the shock wave pushes the liner metal fluid towards center and since there is already metal occupying the center, the metal gets pushed out in two directions, some of the metal gets thrust in the direction of motion and becomes part of the jet or the penetrating portion of the shaped charge, while the rest of the metal gets pushed back towards the explosive and becomes part of the slug, the slow bulky portion of the shaped charge.
The remaining part of the conical liner may take the shape of a flat sheet and the shock wave may then impart additional momentum to the flat sheet giving it a final solid push. The shaped charge finally detaches from its casing.
The fluid metal has a varying velocity with length velocity decreasing farther down. For example, a jet tip of the fluid metal may be traveling much faster than a slug. The result may be an ultra-fine long penetrator traveling at an extremely high speed which may go through armor with a thickness of about six times the diameter of the charge. In accordance with one embodiment of the present disclosure, the speed of the tip of a shape charge may be substantially decreased by an air gap embedded within an armor system of the disclosure.
However, shaped charges are not as effective and efficient to pierce armor from a distance, since a jet of fluid material can continue to stretch and will eventually break apart before it contacts a distant target.
An EFP is a specific type of shaped charge designed to pierce armor from a distance. A wide range of EFPs have been designed depending on the desired effect. An EFP structure may provide a distinct aerodynamic advantage over shaped charges. EFPs are typically shaped as semi-spherical dishes (rather than conical shapes as described above) that may be covered by a metal liner. The metal liner may be copper, or any other suitable metal that behaves similar to a fluid when subjected to extremely high inertial forces.
By having a more shallow dish shape an EFP jet does not become quite as concentrated as a shape charge jet described in sections above. Often an EFP metal becomes a single slug rather than a separate slug and jet. A minor jet may be present near the tip, but for the most part, the slug does not have a defined shape. EFPs typically have a larger slug that stays together better, but may have lower penetration attributes. For example, an EFP may be able to pierce a thickness of steel armor equal to the charge diameter. However, an EFP liner may be concentrated together such that the metal does not break apart before it reaches its target, making it efficient to strike distant targets.
As set forth earlier, geometry of the curvature of the liner before detonation may control the shape an EFP changes into after detonation. Particular shapes may be found to provide optimum aerodynamic and penetration attributes. The shape of an EFP may be important to its ability to penetrate. An EFP with a smaller surface area may penetrate easier. This may be the result of the higher stress that the EFP imparts over a smaller surface area of the armor it is penetrating. This may result in greater penetration. In accordance with one embodiment of the present disclosure, surface area of the tip of an EFP may be increased by an air gap embedded within an armor system.
An EFP may travel at hypervelocity regimes over 6,700 miles per hour. A shock wave that accelerates the metal liner to these types of velocities may cause the metal liner of an EFP to behave as if it were a fluid. Fluid effects caused by the inertial forces generated by the explosion may in part contribute to the EFPs ability to penetrate.
As the fluid from an EFP tip penetrates armor, the armor may exert a drag force upon the tip of the EFP. However, instead of transmitting this force throughout the entire EFP, as would occur if the EFP were a solid, the tip portion of the EFP that is subjected to the drag force, may fall away from the sides of a hole being created in the armor. Thus, instead of slowing down the entire EFP, only a small portion of the EFP may experience drag from the armor while the rest of the EFP maintains its velocity as it travels through the hole in the armor.
Additionally, as the portion of the metal tip gets dragged backwards by the armor, the EFP may reshape itself into a better penetrator. This may result when the edges of the EFP may be somewhat consumed as they are pushed to the rear of the EFP reshaping the EFP to become a thinner and more effective penetrator. For example, material from EFPs may be reshaped into a missile shape. The EFP, due to this reshaped form, effectively slides through the hole formed in the armor, as opposed to having large friction forces from the armor slow the entire EFP. Accordingly, an EFP effectively lubricates the armor walls through which it is penetrating and despite its poor initial shape, is effectively able to reshape and bore through thick armor. In some embodiments, an armor system having layered polylithic composite panels and/or having layered mololithic composite panels, according to some embodiments of the disclosure, may slow the surface tip of an EFP (by contact with certain configurations and orders of polylithic layers and/or panels) causing the rear portions of the EFP to collide into the slower tip portion, which may significantly reduce the reshaping ability of an EFP.
In addition, an EFP during its hypervelocity flight may split into a series of metal blobs or metal particles comprising leaders that are smaller, but travel faster and slugs which may be slower and bulkier. Several leader particles such as a primary leader and a secondary leader and several slugs such as a primary slug and a secondary slug may be present. A good EFP normally has all these metal particles well aligned with out a large pitch or yaw. Accordingly, an armor to protect from such an attack must be capable of withstanding multiple impacts. In some embodiments, configurations and arrangements of the layered composite sheets, polylithic or monolithic, as set forth in certain embodiments, slow down the initial EFP particles thereby causing later EFP particles to crash into the slowed initial EFP particle rather than into an armor layer. Accordingly, embodiments of the present disclosure provide a capability for changing the trajectory of an EFP (or other hypervelocity impact) by causing the particles to misalign.
Much of the lethal damage from an EFP is due to the behind armor effects (BAE). When an EFP penetrates armor, it may launch spall into the vehicle. Spall refers to the fragments of armor that the EFP may cause to break off and accelerate into the interior of the vehicle. This material may be extremely hot and may be moving at an extremely high velocity. As a result, these armor fragments may hit nearly everything within the personnel compartment of the vehicle and may cause extreme damage to the vehicle and equipment inside and injury or death to any occupants.
Damage from EFPs may also result from the overpressure blast that may send highly compressed air outwards at an extremely high velocity. The overpressure alone may cause blindness, deafness, and death. The overall effect of an EFP penetrating a vehicle may be similar to a fragmentation grenade being detonated within the vehicle.
In accordance with one embodiment of the present disclosure, an armor system having layered polylithic composite panels and/or having layered monolithic composite panels, may be capable of significantly reducing destructive capability of a shape charge, an EFP, a high explosive, as well as any high velocity impact by slowing the speed of the respective projectile device.
FIGS. 1A-9C show certain example embodiments of the disclosure relating to one or more armor systems including polylithic armor system 150 and/or monolithic armor system 150 m. However, teachings recognize that other armor systems as described in the present specification may be made and/or modified and used and the invention is not limited to embodiments shown by the drawings.
FIG. 1A-D shows certain embodiments of one armor system 150 comprising a plurality of polylithic armor panels 155 (also referred to layers of armor 155). As set forth earlier, a polylithic panel may comprise composite fibers having more than one direction of weave in a single panel. Additional details regarding polylithic panels according to one or more embodiments of the disclosure are set forth in sections below.
FIG. 1A depicts armor system 150 having at least a plurality of polylithic armor panels 155 a, 155 b, 155 c and 155 n, according to one example embodiment. In other embodiments, additional or lesser number of polylithic armor layers (or polylithic armor panels) 155 may be present in armor system 150. In non-limiting examples, an armor system 150 of the present disclosure may comprise two or more polylithic armor panels 155.
As further depicted in FIG. 1A, an outer side 151 of armor system 150 of the disclosure may refer to a side of armor system 150 that receives initial impact of a projectile 100 and inner side 152 may refer to a side of armor system 150 that is farthest away from the initial impact site of projectile 100.
Projectile 100 may be any high explosive device, such as but not limited to a shape charge, an EFP, an IED, a landmine, a high energy explosive, a ballistic device and/or any hypervelocity impact. However, teachings of certain embodiments recognize that armor systems of the disclosure, exemplified by 150 or 150 m (described later), may provide protection or mitigate the effects of these as well as other types of projectiles that may be operable to penetrate armor.
FIG. 1B shows a cross-section of one polylithic composite armor panel 155, such as but not limited to 155 a of FIG. 1A. Polylithic composite armor panel 155 is comprised of a plurality of layers 140, depicted as 140 a, 140 b, 140 n, according to one example embodiment.
FIG. 1C shows an enlarged view of one layer 140 and shows each layer 140 further comprised of a plurality of sheets 130 according to one example embodiment.
FIG. 1D shows an enlarged cross-sectional view of a layer 140 and depicts a plurality of sheets 130, showing each sheet 130 comprised of a plurality of fibers 120 according to one example embodiment.
The following section describes certain embodiments relating to composition and assembly of polylithic composite armor panels 155 (as shown in FIGS. 1A-4).
In some embodiments, armor layers 155 may be comprised of composite fibers 120. Fibers 120 may be made of a variety of composite materials. Non limiting examples of composite materials that may comprise fibers 120 include e-glass, s-glass, an aramid fiber (e.g., Kevlar), carbon nanotubes, carbon fibers, aluminum fibers and combinations thereof.
A composite armor panel 155 (and 156—described later) of the disclosure may be made of composite materials, often abbreviated as composites. Composite materials may provide lower weight armor solutions as compared to steel counterparts. Composites comprising two or more distinct materials may be made or structured in a vast number of ways. The present disclosure is not limited in any way by the materials or methods by which composites may be made.
According to some embodiments, fibers 120 of composite materials may be woven together and/or sewn together to form fiber sheets 130. Woven sheets 130 may be layered or stacked upon each other with a glue laid out in between each sheet 130. Glue (e.g., a resin) may be used to bind woven fibers 120 (i.e., sheets 130) together to form layers 140.
In some embodiments, for assembly of polylithic composite armor panels 155, a plurality of layers 140 may be placed in a machine that applies a large amount of heat and pressure which causes layers 140 to bind together solidly. This forms a solid composite polylithic armor panel 155. A plurality of polylithic composite panels (e.g., 155 a, 155 b, 155 c, 155 n) may be further layered over each other to form an armor system 150 or an armor solution 150.
Teachings recognize that in certain embodiments, for polylithic composite armor panels, one or more sheets 130 comprised of fibers 120 may not be identical. For example, in one embodiment, each sheet may be comprised of two or more different fiber and/or weave characteristics. In another example embodiment, each sheet may be comprised of fibers of the same material but may have different fiber thickness and/or weave characteristics (e.g., fineness of mesh and/or directions of the weaves).
Several features and characteristics of fibers 120 and the way in which they are woven into sheets may contribute to performance of armor system 150. In some example embodiments, fibers 120 may be made from one or more of a variety of materials. In some example embodiments, fibers 120 may have various thicknesses d. In some embodiments, non-limiting examples of fiber characteristics may include material of fiber, and fiber thickness.
Teachings of certain embodiments recognize that armor systems of the disclosure comprised of sheets having different fiber characteristics may be used to assemble armor panels 155 having different projectile protection abilities.
For example, in one embodiment, a sheet 130 woven or stitched using thick fibers 120 may have a very different performance as compared to a sheet 130 woven or stitched using very fine thin fibers 120 and/or a sheet 130 woven or stitched using medium thickness fibers 120.
The way in which fibers are woven may be referred to as weave characteristics which may also vary the performance and qualities of a sheet 130 or an armor panel 155 composed thereof. Weave characteristics may comprise one or more of the following non-limiting exemplary factors such as direction of weave, fineness of mesh, type of weave, and pattern of weave.
Teachings of certain embodiments recognize that armor systems 150 of the disclosure comprised of sheets 130 having different weave characteristics may be used to assemble polylithic armor panels 155 having different projectile protection abilities.
In some embodiments, a polylithic composite armor layer 155 may have one or more different weave characteristics. For example, fibers 120 of a polylithic panel may have more than one direction of weave in a single composite panel.
A direction of weave may be described the direction of a fiber in the weave. For example, a non-limiting example of a directions of weave is a [0°/90°] weave, which indicates that fibers 120 run in two directions, a horizontal [0°] and a vertically [90°]. Another example direction of weave is a quadraxial weave also referred to as a [0°/+45°/−45°/90°]s weave. This weave comprises fibers that run in four primary directions, hence “quadraxial”. The “s” is an abbreviation that refers to symmetric. The unabbreviated notation would be described weave. Directions as a [0°/+45°/−45°/90°/90°/−45°/45°/0°] of weaves are not limited to the examples described here and weaves in many other directions as known to one of skill in the art may be used in various embodiments described here.
Certain embodiments recognize that in an armor system having sheets with more complex weave directionality (e.g., a [0°/+45°/−45°/90°]s weave), the presence of a larger number of angles in the sheets may advantageously increase the energy absorbing capacity of the armor system.
In some embodiments, teachings recognize that resin concentration may change material properties of a composite. For example, use of more resin may cause an armor panel to be harder and less flexible. Teachings recognize that in certain embodiments, combination of resin concentration and/or fiber characteristics and/or weave characteristics may allow control of flexibility and hardness in composite armor panels of the disclosure.
FIGS. 2A, 2B and 2C depict another weave characteristic, the fineness of weave also sometimes called mesh size. FIG. 2A shows an example thick weave 111 a in an example sheet 130. In some embodiments, a thicker weave 111 a may have more gaps and/or a larger mesh size due to being woven more loosely. Accordingly, in some embodiments, sheet 130 comprising thick weave 111 a (or larger mesh size) may be flexible and soft. While a thick weave 111 a may not result in very strong sheets 130, layers 140, panels 155 and/or portions thereof, thick weave 111 a may provide flexibility.
FIG. 2B shows another sheet 130 having an example medium weave 111 b (or medium mesh size) and FIG. 2C shows sheet 130 having an example fine weave 111 c (or small mesh size), according to some example embodiments. In some embodiments, a fine weave 111 c may have very few or very small gaps (mesh size) since fibers 120 may be woven more tightly. In some embodiments, a fine weave 111 c may have substantially no gaps (ultra fine mesh size). Accordingly, in some embodiments, sheet 130 comprising fine weave 111 c may be rigid and strong. In some embodiments, a sheet 130, a layer 140, a panel 155 and/or portions thereof comprising fine weave 111 c may provide strength to ward off a projectile 100.
One of skill in the art will recognize that the teachings are not limited to the mesh sizes shown in FIGS. 2A-C and several other intermediate and combination mesh sizes may be present. Also the pattern of weave may change the size of the mesh as will fiber thickness and fiber type.
Teachings of certain embodiments recognize that flexibility of an armor panel may be controlled in part by the nature of fibers, thickness of fibers, directionality of weave and/or fineness of mesh (also called mesh size).
For example, in one embodiment, a technical advantage of a layer or portion of a layer having a thick weave 111 a to an armor panel 155 may include the capability to flex in response to a projectile 100 thereby increasing the dwell time of projectile 100 and reducing the force exerted force by the projectile device.
However, a very flexible panel may not be able to sustain a very larger impact force. Also over flexing may cause a deformation of the armor and injure occupants on the inner side. Accordingly, teachings of certain embodiments recognize that a balance between hardness of a panel and flexibility of a panel may provide the best ballistic protection.
Certain embodiments recognize optimal use of delamination, i.e. peeling away of a sheet from an adjacent sheet, to dissipate energy of an incoming projectile. Teachings of certain embodiments recognize improving energy absorption of an armor system through physically breaking glass threads. For example, certain embodiments recognize that an armor system having sheets with a finer mesh has more bonds that must be broken.
Accordingly, FIG. 3A depicts a polylithic armor panel 155, according to one embodiment, having a first flexible layer 140 a comprising one or more sheets 130 (not expressly depicted) having a thick weave 111 a (or large mesh size 111 a) which may be followed by a second layer 140 b comprising one or more sheets 130 (not expressly depicted) having a fine weave 111 c (or small mesh size). In the embodiment described above, layer 140 a is located toward the outer side 151 of panel 155 and provides a flexible layer which increases dwell time of projectile 100 following initial impact. Layer 140 b is located toward the inner side 152 of panel 155 and is the strong layer that may have capability to absorb force exerted by projectile 100 on the layer above.
In some embodiments, combining the two effects of first increasing dwell time and thus increasing impact time using an outer layer 140 a having a larger mesh 111 a followed by second, increasing the amount of force absorbed by using an inner layer 140 b having smaller mesh (comprised of fine weave sheets) in response to a projectile 100 may together reduce the overall impact of projectile 100. For example, a technical advantage of embodiments having such a combination may include the capability to change the trajectory of projectile 100.
FIG. 3B shows an enlarged view of an example polylithic panel 155 having at least three layers 140 a, 140 b and 140 c. In this example embodiment, outer side layer 140 a may have a thicker weave 111 a, the middle layer 140 b may have medium weaves 111 b and the inner side layer 140 c may have finer weaves 111 c. Accordingly, first layer 140 a is a flexible layer followed by second layer 140 b with medium flexibility and a third layer 140 c being a more strong and rigid layer.
FIG. 3C shows an enlarged cross-sectional view of an example polylithic panel 155 having at least two layers, the outer layer 140 a having a plurality of sheets 130 comprised of thicker fibers 120 having a thickness d₁and the inner layer 140 b having a plurality of sheets 130 comprised of finer fibers 120 having a thickness d₂, where d₁>d₂according to one example embodiment.
According to some embodiments, having a more flexible composite panel toward the outer side of an armor system may provide an ability to bend or flex backwards slightly following an impact thereby causing a longer dwell time. Increasing the impact time may advantageously decrease the amount of force exerted by a projectile upon an armor panel at any given point of time.
FIG. 4 depicts one example embodiment showing a panel 155 of an exemplary armor system 150 having multiple polylithic armor panel layers 140, wherein at least two layers have a different Young's modulus.
Some embodiments of the disclosure relate to monolithic composite armor panels and systems. Accordingly, FIG. 5A shows an example monolithic armor system 150 m having a plurality of monolithic composite armor panels, such as 156 a, 156 b, 156 n, according to one example embodiment. However, teachings recognize use of additional or lesser number of monolithic armor layers (or armor panels) 156 in monolithic armor system 150 m. In non-limiting examples, a monolithic armor system 150 m of the present disclosure may comprise two or more layers of monolithic armor panels 156.
As shown in FIG. 5A, according to some embodiments, a monolithic armor system 150 m may comprise a plurality of monolithic composite armor panels 156 layered from an outer side 151 to an inner side 152 of monolithic armor system 150 m.
FIG. 5B shows a cross-section of one example monolithic composite armor panel 156 further comprising a plurality of layers 141.
FIG. 5C shows an enlarged view of one example layer 141 and shows each layer 141 may be further comprised of a plurality of sheets 131.
FIG. 5D shows an enlarged cross-sectional view of an example embodiment of layer 141 and depicts details of plurality of sheets 131 showing example fibers 121 comprised in each sheet 131, according to one example embodiment.
A monolithic composite armor panel 155 may also comprise one or more adhesive agents such as a resin.
Several features described above for embodiments relating to structure of polylithic armor panels 155 and systems 150 are similar to those of monolithic armor panels 156 and systems 150 m. However, as set forth above, one distinguishing feature between a monolithic and a polylithic composition is that all sheets comprised in one monolithic panel have one respective direction of weave. For example, in a non-limiting embodiment, all sheets comprised in one monolithic composite armor panel may have a direction of weave (also called weave directionality) of [0°/90°] that may be used repeatedly to form a panel of a respective thickness (e.g., 0.5 inches or 1 inch).
In some embodiments, since the weave directionality is constant throughout a monolithic panel, the concentration of a resin in the panel is also substantially uniform.
Accordingly, in some embodiments, a sheet 131 as shown in FIG. 5D, comprised in a layer 14 of a monolithic panel 156 may comprise one or more fiber types 121 (i.e., fibers made of different composite materials as described in sections above for fibers 120). In some embodiments, a sheet 131 may comprise fibers 121 having one or more different fiber thickness d. In some embodiments, a sheet 131 comprised in a monolithic panel 156 may have one or more respective weave meshes having respective thick fineness of mesh such as 111 a, medium fineness of mesh shown as 111 b and fine mesh size 111 c as exemplified in FIGS. 2A-C.
FIG. 6A shows an enlarged view of monolithic panel 156 f having at least three layers 141 comprising sheets (not expressly depicted) having thicker flexible weaves 111 a, according to one example embodiment. Accordingly 156 f may represent a flexible and/or softer monolithic panel.
FIG. 6B shows an enlarged view of a monolithic panel 156 r having at least three layers 141 comprising sheets (not expressly depicted) having finer mesh sizes 111 c (also referred to as rigid weaves), according to one example embodiment. Accordingly 156 r may represent a rigid and/or hard monolithic panel.
FIG. 6C shows an enlarged cross-sectional view of an example monolithic armor system 150 m comprised of at least two monolithic panels 156 f and 156 r as described in the paragraphs above. As depicted first monolithic panels 156 f is located on outer side 151 of armor system 150 m and second monolithic panel 156 r is located on inner side 152 of armor system 150 m, according to one example embodiment.
According to some embodiments, an armor system may be comprised of layers of thin monolithic panels, the thin monolithic panels having a thickness of less than or equal to 0.5″.
As detailed earlier, having a more flexible composite panel toward the outer side of an armor system allows for flexing backwards slightly following an impact thereby causing a longer dwell time and increasing the impact time may advantageously decrease the amount of force exerted by a projectile upon an armor panel at any given point of time.
FIG. 7 depicts a vehicle 20, such as but not limited to a military vehicle, that may be equipped with an armor system of the disclosure such as a polylithic armor system 150 or a monolithic armor system 150 m, in accordance with certain example embodiments. An armor system 150 may have a plurality of polylithic armor panels 155 as described. An armor system 150 m may have a plurality of monolithic armor panels 156 as described. Armor system 150 or 150 m may be comprised on exterior of vehicle 20. Occupants and equipment of vehicle 20 may be protected by armor system 150 or 150 m from the penetrating effects of a projectile (not expressly depicted) which may target vehicle 20. Vehicle 20 may be maneuverable and effective on a battlefield while it is equipped with an armor system 150 or 150 m in accordance with embodiments of the present disclosure.
According to some embodiments, present armor systems such as 150 and/or 150 m may be from about 1 mm to several inches in thickness. Other armor systems that do not employ polylithic or monolithic composite panel combinations as taught herein may be considerably heavier and thicker. For example, conventional armor systems, may be several inches thick. In another example, mere addition of two existing panels of armor to an existing conventional armor system may add an additional weight of about 20 lb/ft²or more depending on the type of armor material used. If vehicle 20 were equipped with any existing armor system or armor system solution, its maneuverability and effectiveness in protecting against projectiles 100 as described here may be diminished.
FIGS. 8A and 8B show an exemplary path of an example explosively formed penetrator (EFP) 100 through a prior art armor system 150 b not having either the layered polylithic or layered monolithic composites, as taught in some of the present embodiments. FIG. 8A depicts an example shallow-disk shaped EFP 100 making contact with a first layer of armor 155 a located on an outer side 151 of the prior art armor system 150 b and FIG. 8B depicts the EFP 100 now formed into a missile-shaped structure as it penetrates through all the layers of prior art armor, 155 a, 155 b and 155 c. As depicted, EFP 100 is now reshaped into a missile shaped structure and slides through armor as it penetrates through layers of the prior art armor system 150 b. Since EFP 100 may be fully constrained within armor material of armor system 150 b the EFP stays aligned on its trajectory through all the layers of the prior art armor system 150 b.
FIGS. 9A, 9B and 9C illustrate an exemplary path of an example EFP 100 through one embodiment of a layered composite armor system 150 or 150 m (monolithic or polylithic) of the disclosure wherein FIG. 9A depicts an example shallow-disk shaped EFP 100 contacting an outer side 151 of the armor system 150 or 150 m. FIG. 9B depicts the EFP as it penetrates through a first armor panel 155 a or 156 a which may, in some embodiments, flex and slow EFP 100.
In some embodiments, armor panels 155 a or 156 a may flatten the surface-tip of EFP 100 and diminish its shape-change ability.
In some embodiments, armor panel 155 a or 156 a may slow the penetrating tip of projectile 100, thereby causing a collision of faster moving rear portions of the projectile 100, causing the projectile tip to gain an increased surface area.
In some embodiments, the entire shape of a projectile may be changed following contact with 150 or 150 m.
FIG. 9C illustrates path and shape of EFP 100 as it penetrates through a second armor panel 155 b or 156 b which may in some embodiments, further flex and/or additionally slow impact of EFP 100. In some embodiments, additional slowing may further flatten the surface tip and additionally reducing shape change ability of EFP 100, according to one example embodiment.
In some embodiments, subsequent encounters with two or more composite layers arranged in accordance with various advantageous configurations as set forth here may render EFP 100 unable or ineffective to penetrate armor layer 155 c or 156 c leaving the occupants and equipment behind protective armor layer 155 c or 156 c protected. In some embodiments, one or more composite armor layers of the disclosure may increase the overall energy absorption capacity of armor system 150 and/or 150 m.
Existing armor systems operate on the hard to soft concept and often have hard metal armor panels for increased hardness. Teachings of present embodiments recognize that flexibility of a fiber system causes more substantial increases in protection relative to a metal system. In some embodiments, this may be as fibers in tension may perform significantly better than fibers being sheered.
Finely woven high resin panels, being strong and rigid, have been a choice in several existing armor solutions for providing protection against projectiles. However, the present inventors have shown that harder panels placed toward initial impact sites in an armor system absorb significantly less energy.
In contrast to present thoughts in the art, teachings of certain embodiments recognize the need for a fine tuning of hardness and flexibility of armor panel layers in an armor system. Accordingly, some embodiments relate to having a more flexible panel in the front and a more rigid panel in the back for energy absorption purposes. In some embodiments, a flexible front panel may increased dwell time and change the trajectory and shape change properties of a projectile. In some embodiments, the more rigid back panels may reduce the exerted force providing increased protection. Teachings of certain embodiments recognize that merely having a flexible panel may not sustain a larger force. Teachings of certain embodiments recognize and teach the balance between hardness and flexibility for optimal protection.
Composites of the disclosure may absorb energy from a projectile in a number of ways. In some embodiments composites may absorb energy by friction, by delamination, and/or by breaking of molecules of the composite fibers. Friction has been used for traditional armor systems and is normally one of the most effective methods for bullets. However, present teachings recognize that for EFPs, due to their fluidic ability to re-shape, friction alone may not be effective.
Present teachings recognize that in some embodiments, delamination may require breaking of numerous bonds, e.g., of the resin glue, all along the length of a composite sheet 130. Accordingly, present teachings use in part delamination as an effective method of absorbing energy because it allows for a small impact zone to be absorbed over a large surface area.
Teachings also recognize the use of energy absorption occurs through physically breaking threads of fiber 120 or 121. Accordingly to some embodiments, teachings recognize that finer mesh have more bonds that must be broken. Accordingly, in some embodiments, composite polylithic (or monolithic) panels having a larger number of angles, such as a [0°/+45°/−45°/90°]s may be used advantageously for absorption of more energy.
Teachings of certain embodiments recognize the use of fiber thickness and weaves may be fine tuned and located at positions within the armor system in relation to the direction and force of impact.
Modifications, additions, or omissions may be made to the systems and apparatuses described herein without departing from the scope of the invention. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. Additionally, operations of the systems and apparatuses may be performed using any suitable logic. As used in this document, “each” refers to each member of a set or each member of a subset of a set.
Although several embodiments have been illustrated and described in detail, it will be recognized that substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the appended claims.
To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims to invoke paragraph 6 of 35 U.S.C. §112 as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.

Claims

1. An armor system comprising:

a plurality of polylithic composite armor panels;

each of the polylithic composite armor panels comprising a plurality of layers;

the plurality of layers comprising at least two layers having a different Young's modulus;

each of the plurality of layers comprising a plurality of sheets;

the plurality of sheets comprising one or more fibers; and

the plurality of sheets having one or more respective weave characteristics.

2. The armor system of claim 1, wherein the one or more fibers have a type comprising an e-glass fiber, an s-glass fiber, an aramid fiber, a carbon nanotube, a carbon fiber, an aluminum fibers and combinations thereof.

3. The armor system of claim 1, wherein the weave characteristic comprises a direction of weave, a fineness of mesh, or a weave pattern.

4. The armor system of claim 3, wherein the direction of weave comprises a [0°/90°] weave, a [0/+45°/−45°/90°]s a weave, and combinations thereof.

5. The armor system of claim 3, wherein the fineness of mesh comprises a finely woven mesh, a coarsely woven mesh, a thick mesh, a medium weave mesh, a thin mesh, intermediates or combinations thereof.

6. The armor system of claim 1, further comprising a resin to bind at least two of the one or more fibers or at least two of the plurality of sheets.

7. The armor system of claim 1, wherein the plurality of polylithic composite armor panels are layered from an outer side of the armor system to an inner side of the armor system, the outer side being the side of initial projectile impact and the inner side being the side farthest away from initial projectile impact.

8. The armor system of claim 7, wherein each of the polylithic composite armor panels comprises at least two layers.

9. The armor system of claim 8, wherein at least a first layer of the two layers comprises sheets having a thicker weave, the first layer located toward the outer side of the armor system; and

at least a second layer of the two layers comprises sheets having a finer weave, the second layer located toward the inner side of the armor system.

10. The armor system of claim 1, wherein each of the polylithic composite armor panels comprises at least three layers.

11. The armor system of claim 10, wherein:

at least a first layer of the three layers comprises sheets having a thicker weave, the first layer located toward the outer side of the armor system;

at least a second layer of the three layers comprises sheets having a medium weave, the second layer located toward a middle side of the armor system; and

at least a third layer of the three layers comprises sheets having a fine weave, the third layer located toward the inner side of the armor system.

12. An armor system of claim 1, comprised in a vehicle.

13. An armor system according to claim 1, operable to improve resistance to impact by a shape charge, an explosively formed penetrator (EFP), an improvised explosive device (IED), a ballistic device or a hypervelocity impact.

14. An armor system comprising:

a plurality of polylithic composite armor panels;

the plurality of polylithic composite armor panels layered from an outer side of the armor system to an inner side of the armor system, the outer side being located toward an initial projectile impact site and the inner side being located away from the initial projectile impact side;

each of the polylithic composite armor panels comprising a plurality of layers;

each of the plurality of layers comprising a plurality of sheets;

the plurality of sheets comprising one or more fibers;

the plurality of sheets having one or more respective weave directionality and one or more respective weave meshes;

the plurality of sheets comprising one or more different fiber thickness; and

at least one of the polylithic composite armor panels has at least one of the layers comprising thicker fibers toward the outer side of the armor system and finer fibers toward the inner side of the armor system.

15. The armor system of claim 14, wherein each of the polylithic composite armor panels comprises at least two layers.

16. The armor system of claim 15, wherein:

at least a first layer of the two layers comprises sheets having a thicker weave, the first layer located toward the outer side of the armor system; and

17. The armor system of claim 14, wherein each of the polylithic composite armor panels comprises at least three layers.

18. The armor system of claim 17, wherein:

19. An armor system comprising:

a plurality of monolithic composite armor panels;

the plurality of monolithic composite armor panels layered from an outer side of the armor system to an inner side of the armor system, the outer side being located toward an initial projectile impact site and the inner side being located away from the initial projectile impact side;

each of the monolithic composite armor panels comprising a plurality of layers;

each of the plurality of layers comprising a plurality of sheets;

the plurality of sheets comprising one or more fibers having one or more different fiber characteristics;

the plurality of sheets having at least one respective weave directionality;

the plurality of sheets having one or more respective weave meshes; and

at least one of the monolithic composite armor panels having a thicker flexible weave mesh located toward the outer side of the armor system; and

at least a second of the monolithic composite armor panels layers comprising layers having a finer rigid weave mesh located toward the inner side of the armor system.

20. The armor system of claim 19, wherein the monolithic panel has a thickness of less than or equal to 0.5″.