People have tried to protect themselves against projectiles for centuries. This evolved from Hand-held shields made from stretched leather and wooden frames to complete wooden shields. Eventually to full steel shields, combine with chain-mail body armor, specialty woven silk fabric, and finally to specialty metals. As the speed and type of projectiles used have changed so too has combat with the use of BODY ARMOR.
The type of protection required was based upon the type of projectiles that were delivered. These were initially clubs or handheld spears, with developments later that would project an object through mechanical means, such as hand-drawn bow and arrow or mechanical crossbows. Currently protection is based upon projectiles delivered at very high velocity through handheld devices commonly referred to as firearms. For reference, the average speed of sound is 1126 feet/sec.
Protective armor can be made from a variety of polymeric materials. Components and structures that are shrapnel or blast-resistant. Materials like ceramic plates, ultrahigh molecular weight polyethylene (UHMWPE), and poly-aramid are all commonly used. These are also known as "KEVLAR", and polymeric matrixes that have fiber-reinforced structure, made from one or more of the above-mentioned polymers have been shown to exhibit ballistic dampening.
These are some of the characteristics. Figures 2, 3 & 4 show examples of current armor systems. This protective type of soft armor was first developed in 1943 and was called "The Protective Type Soft Armor". A "flak jacket", to reduce the effects of shrapnel and wounds, was used during World War II. With much Development was completed, and the late 1950's saw the introduction of soft armor protection. However, it was heavy. As the Vest M-1951 or the Armored Vest M-1955. Protective vests could be combined Layers of poly-aramid fabric, and composite plates made from compressed fiberglass laminates. The Doron Plate. Figure 1. Cartridge Comparison L. to R.:.22LR,.380 ACP. 9 mm.45 ACP..357 Magnum..44 Magnum. 5.56X45mm, 7.62X35mm, 7.62X51mm Figures 2, 3, & 4 L to R: Soft Armor and Composite Armor.
Figure 5 shows an example of the M-1955 vest. Figure 5. M-1955 Armored Vest Possessing positive physical and performance characteristics, but not limited to High strength-to-weight ratios and high impact resistance. These materials can be subject to shock loading. These include Flaking and surface chipping can make them friable. It is also hard to make a durable. These materials can be protected with a protective coating or an aesthetic long-lasting finish. These drawbacks are especially noticeable in applications like the production of blast Location of shrapnel armor in different wear and traffic areas, such as the floors Wall regions and aircraft of various motorized vehicles. Panels and other constructions Attached to the vehicle structure are pieces made from suitable armor material They provide protection for the occupants. These panels provide armored protection that is more than adequate.
The materials are vulnerable to wear such as chipping, flaking and gouging as well as items like Ordinance-related cargo and ordinance-related items can be dragged or dropped onto panel surfaces during routine usage Operation These materials can be difficult to paint on or coat because of the lower adhesive. The panels are made of polymeric materials that have certain characteristics.
It would be ideal to create a coating composition that can be used to coat at A friable substrate should not have more than a small portion of its surface. A coating is also recommended It can be used to cover a substrate and stick to it. It would It is also desirable to have a coating composition that adheres well to the substrate With challenging adhesion properties. It would be nice to apply a coating Without unduly compromising, composition that can be used with an armor panel The panel's blast or ballistic resistance.
You can achieve armor protection by using different layers of UHMWPE and/or Polyaramid fiber sheets Type IIA requires approximately 18 sheets. Type II at 21 sheets, and Type IIIA with 35 sheets or layers. It is interesting that soft armor can be found in both Type IIA with 21 sheets and Type IIIA at about 35 sheets or layers. Panels are sold as backpack inserts and brief cases for students. Protective coatings for play Plural-component polyurea elastomeric technology (PUA), was created after the spray application.
A variety of applications were demonstrated when the technology was introduced in late 1980s. Although most of the applications are related to protective coatings, there are some other areas. One Spray applied technology was used to create shooting targets (called "Ivan's") for the purposes of the US Military Training.6 To produce a variety, the elastomeric Polyurea system was applied to an open mold. For military training exercises, the polyurea was used to create and "human-form” targets. The polyurea was used at Dry film thickness (DFT), 125-250 mils (3.1-6.4 mm). These polyurea targets can be shot at Complete penetration was observed in Type IIA-Type IV classifications (from Tab 1) The projectile. Multiple shots are possible due to the elastic properties of the polyurea. The target was not significantly damaged. There was no stopping power for the projectile. The polyurea produced an interesting result with the holes "resealing" themselves. Later, chopped aramid fiber was introduced to the polyurea spray pattern. System to ensure true ballistic properties.7 - 8.
Figures 6 and 7 illustrate the effects of aromatic polyurea on entry and exit points of a panel. At a DFT of approximately 250 mils (6.4mm).
Recent work has produced the same results that was seen in the 1980s. To help, the polyurea system could also be used on existing steel components in military vehicles. The polyurea does not reduce the effects of small arms fire and blast shrapnel, but it is NOT BULLET. PROOF! 9 - 13 The polyurea alone would not be enough to stop bullet travel. It can be applied to a thickness well above 1 inch (2.54 cm), which adds considerable dimension and weight.
A 1 ft2 polyurea piece (0.1 m2) of 1-inch thickness would be over 5.5 lbs. Kilograms This illustration was made using different thicknesses of an aromatic polyurea (elastomer) to illustrate the point. Impact from projectiles listed in the NIJ Classification Table I. An 80 mil Layer (2 mm) was exposed to three rounds with a Type I Classification.22-cal projectile (Type I Classification). The polyurea was heated to 80° F (27° C). The same procedure was used on a similar piece at 6oF (-15oC). To show the PUA's flexibility at low temperatures, These are shown in Figures 8 and 9. Figure 8 and 9. It was used. 14 The hard system (Shore D50) showed cracking due to the high velocity impact. area, while the soft system (Shore A80) did not. This is quite normal given the High velocity projectile
Protecting the "Plates". Given the above discussion, and the fact that polyurea is not bulletproof by itself, where do we go from here? Technology fit? Most ballistic plates consist of soft armor made with polyaramid fibers. Composite pieces made of steel, ceramic, or fiber must be protected against any damage. It will be ineffective. Ballistic plates are subject to bullet fragmentation. injury or plate shattering following multiple hits. The polyurea coating system applied to the plate is not recommended. The ballistic part is not to be used, but to trap bullet fragmentation and protect the plates resulting injury or damage.15 The 1950's Flak Jacket, as mentioned earlier, contains both rigid and soft armor.
The rigid armor consisted of the 130 mil (3.35 mm) Doron plates, which were encased with nylon and cotton fabric. Place in the pockets of the vest by rapping. Rapping serves two purposes: Trapping projectile fragments. Encapsulating the ballistic panel in a Trapping material isn't a new idea. Figure 10 illustrates the fabric-encapsulated plate. Figure 11 shows the same plate after an impact with a Type IIIA projectile. This is the case. .45 ACP, the common round for that era. The fabric panel, as seen, is efficient, but significant. Panel damage is noted.
A 10" X10" test panel of polyurea-protected UHMWPE composite panels was used to demonstrate the effectiveness. (25.4 cm X 25.4 cm) Composite panel of overall A thickness of 20mm was subjected 3 rounds 7.62 rifle caliber projectile. The 20 mm plate It was made up of 18mm thick UHMWPE. Encapsulated in 40 mils (1mm) of polyurea Each projectile contained 155 grains (10g) With a velocity of 2000 feet/sec (610 meters/sec), Energy of 1365 ft.lbs force (1850 Joules). This This is a Type III (rifles), classification All 3 rounds were contained within the composite panel. The first 1/4 inch of total panel thickness is included with no Complete penetration The entrance hole is in the polyurea coating was 2 mm thick. The backside The impact was achieved by bulging the panel. The applied polyurea coating has been damaged. The effectiveness of the following figures is shown in the following series of graphs This polyurea composite panel is made from a bullet Nature is proof.
What happens when a projectile of high velocity impacts a hard-ballistic plate? The projectile Completely disintegrates and will splatter high-velocity shrapnel at 90 degrees (perpendicular). The direct area of impact. The shrapnel can travel at high speed and cause significant damage. Damage to the outer areas. Figures 2 through 6 show the effects of both coated and uncoated. Ballistic panels and protected polyurea ballistic panels for projectile fragmentation The "trapping" effect. Figures 19-20 show the effects of high velocity impacts on a panel made from ballistic steel. The panel He was enclosed in a "soft" zone using cardboard and paper. In Figure 20, you can see the outlying. The "soft" area can be completely cut using a sharp knife or, more descriptively, a buzzsaw. To minimize or eliminate shrapnel dispersion from projectile impacts The ballistic panel and the application of an eleastomeric, tough polymer system such as polyurea Spray coating can be used. This coating can be applied in a variety of thicknesses, depending on the application. Depending on the NIJ classification level. The shrapnel effect will be dissipated by this layer. You can even trap it completely. Figures 21-22 show the effects of projectile impact upon a polyurea-coated ballistic panel. It is important to note that there was no shrapnel splash (Figure 21), and that the projectiles were fully trapped Figure 22: Between the coating layer (Figure 22) and the ballistic panel
As mentioned previously, the polyurea technology has an unexpected advantage over the ballistic work of 1987. After the projectile passes through, the elastomeric properties of the System allowed for penetration to reseal. This has a fascinating lubricating effect. The projectile's polymer is an important feature in normal coating and liner work. The coating may be punctured by nails or bolts in some cases. This reduces membrane leakage. This is particularly important for common. This technology is used for waterproofing. How does this apply to ballistic applications, however? Storage tanks are often used in many cases. These tanks, whether permanent or mobile, can contain highly flammable substances. These tanks can be found in They may also be shot at in hostile areas. Although an explosion or fire is unlikely, a projectile could cause a spark that ignites the flammable fuel. Coating These structures are made with an elastomeric system of polyurea systems. The leakage is reduced and the steel is not as hot. Substrat is protected from sparking from projectiles This is illustrated by a 1/8 inch (3.18 mm), steel plate coated with about 100 mils (2.5). (mm) of an elastic aromatic polyurea system. The steel plate was prepared according to SSPCSP 5, White Metal Blast Cleaning. It has a profile of two mils (50 microns). 16 These figures show the sealing power of a polyurea system on a substrate After being exposed to projectile impact. These projectile cartridges represent the most effective. Common in hostile areas (Type III rifles).
The steel plate's exit holes are wider than the actual diameter. Projectiles The applied polyurea is well bonded to steel around it. hole, and "re-sealed” the projectile entry hole. A device was attached to the back of the panel made from steel in order to test the sealing ability. Exit hole. The fluid was then introduced to the device and pressurized to determine the desired pressure. Pressure to demonstrate fluid leakage at the projectile entry area (Figure 28). The liquid used At 77oF (25oC), the viscosity was 1 centipoise, 1 millipascal. These Results are listed in Table III.
Polyurea is not a product, but a technology. Like other coating technologies, polyurea is a technology. There is no "one-size fits all" solution for polyurea technology. There are two types of basic systems for this area: one that provides ballistic trapping effects and one that allows for the Sealing effect. The general characteristics of both systems are shown in Table IV.
CONCLUSION This paper demonstrates how protective coatings such as polyurea elastomer can be applied. Coating technology can provide personal protection. Polymeric composition Systems can be used in a wide range of coating applications, including those with friable and easily combustable materials. Materials with poor adhesion properties and substrates that are damaged may be rejected. Particularly, The compositions shown here are materials that can be used for blast resistance coatings These panels are shrapnel-resistant and can be used for other purposes. This world is becoming more violent. It is vital to protect our military, law enforcers, and citizens. Protective coatings This area is dominated by polyurea technology. Before you make a decision, however Spray yourself with polyurea. But remember that polyurea is not bulletproof by itself! Oh! Joe the Stranger and Joe? Joe the Stranger? He could have been injured by the fragmentation of projectiles if he didn't wear a poncho.
0 Comments