Ballistic vest or bulletproof vest , often called bulletproof vest , is a personal armor item that helps absorb impact and reduce or stop penetration to the body from firearm-trigger projectiles and shrapnel from explosions, and worn on the torso. The soft vest is made of many layers of woven or laminated fibers and can protect the wearer from small caliber rifles and projectile rifles, and small pieces of explosives such as hand grenades.
These vests often have ballistic plates inserted into the vest. Metallic or ceramic plates can be used with a soft vest, provide additional protection against the rifle round, and metal components or layers of woven fibers that can tightly provide soft armor resistance to stab and slash attacks from similar knives and melee weapons. Soft vests are usually worn by police forces, civilians at risk of being shot (eg, national leaders), security guards, and bodyguards, while hard-boned vests are mainly worn by combat troops, police tactical units, and hostages. rescuers.
Body armor can combine ballistic vests with other protective clothing, such as a combat helmet. Vests intended for police and military may also include shoulder protective components and ballistic side guards, and bomb disposal officers use heavy armor and helmets with face shield and spinal protector.
Ballistic vests use a very powerful fiber layer to "capture" and damage the bullet, mushroom it into a disc shape, and spread its power to a larger part of the vest fiber. The vest absorbs energy from the shaped bullet, making it stop before it can actually penetrate the textile matrix. Some layers can be penetrated but when the bullet changes shape, energy is absorbed by larger and larger fiber areas.
While vests can prevent penetration of bullets, vests and wearers still absorb the bullet impulse. Even without penetration, heavy bullets produce enough power to cause blunt object trauma under a collision point. The vest specification will usually include both the penetration resistance requirements and the limit on the amount of impact strength delivered to the body.
On the other hand, some bullets may penetrate the vest, but still provide low damage to the wearer due to their loss of speed and/or small form/mass.
Vests designed for bullets offer little protection against blows from sharp equipment, such as knives, arrows or ice breakers, or from bullets made from non-deformable materials, for example, containing non-lead steel cores. This is because the collision strength of these objects remains concentrated in a relatively small area, allowing them to puncture the fiber layer of most bulletproof fabric. Instead, the puncture vest provides better protection against sharp equipment, but is generally less effective against bullets.
Textile vests can be augmented with metal plates (steel or titanium), ceramics or polyethylene which provide extra protection for vital areas. This hard armored plate has proven effective against all pistol bullets and rifles. This enhanced ballistic vest has become the standard in military use, because the soft body protective vest is ineffective against the rifle of military weapons. Turnkey and police often wear vests specially designed for sharp weapons and sharp objects. These vests may combine textured para-aramid textiles and laminates or metal components.
Video Bulletproof vest
History
early modern era
In 1538, Francesco Maria della Rovere commissioned Filippo Negroli to make a bulletproof vest. In 1561, Maximilian II, Holy Roman Emperor was recorded as testing his armor against firearms fire. Similarly, in 1590 Sir Henry Lee expected his Greenwich armor to be "proof gun". Its actual effectiveness was controversial at the time. The "bullet" etymology and adjectives "evidence" in the late 16th century show that the term "anti-bullet" originated shortly thereafter.
During the British Civil War Oliver Cromwell's Ironside Cavalry was equipped with a Capeline helmet and an anti-gravel protective layer composed of two layers of armor plates (in subsequent research involving X-rays, a third layer was found which was placed between the outer and inner layers). The outer layer is designed to absorb bullet energy and a thicker inner layer stops further penetration. Armor will be left very dented but still serviceable. One of the first recorded descriptions of the use of soft armor was found in medieval Japan, with armor having been produced from silk.
Industrial era
One of the first examples of bulletproof armor sold commercially by tailors in Dublin, Ireland in the 1840s. The Cork Examiner reported on his line of business in December 1847:
The daily melancholy announcement of the killing now embarrassing the state, and the murderers allowed to walk quietly and against the law, has prompted me to build a clothing, gunshot and ball-proof so everyone can be protected, and possible to restore the killer's fire, and thus immediately stop the cowardly behavior that has robbed the lives of so many excellent and precious people, spread terror and sorrow through the state. I hope within a few days to have a specimen clothing on sight in my warerooms.
Another soft ballistic vest, Myeonje baegab, was found in Joseon, Korea in the 1860s shortly after France's campaign against Korea. Heungseon Daewongun ordered the development of bullet-proof clothing because of the increasing threat from Western forces. Kim Gi-Doo and Gang Yoon found that cotton can protect against bullets if 10 layers of cotton cloth are used. The vest was used in combat during the United States expedition to Korea, when the US Navy attacked Ganghwa Island in 1871. The US Navy caught one of the vests and took it to the US, where it was kept at the Smithsonian Museum until 2007. The vest had been shipped back to Korea and is currently on display to the public.
Simple ballistic armor is sometimes built by criminals. During the 1880s, a group of Australian bushranger led by Ned Kelly made basic armor from the plow. At this time the Victorian Government has a reward for the arrest of a Kelly Gang member at £ 8,000 (equivalent to 2 million Australian dollars in 2005). One of the goals stated by Kelly is the establishment of the Republic in Northeast Victoria. Each of the four Kelly gang members fought in a hotel wearing a suit of armor made out of a plow package. Seal maker (Lennon Number 2 Type) found in some plates. The armor covers the torso, upper arm, and upper leg of the man, and is worn with a helmet. The clothes were crafted roughly on the river bed with temporary temps and a log as a muffled foundation. The clothes have a mass of about 44 kg (96 pounds) but ultimately there is no point because the clothes do not have protection for the feet and hands.
American criminals and rifles Jim Miller is famous for wearing a steel chest cover over his skirt coat as a body armor. This plate saved Miller on two occasions, and it proved very resistant to bullet pistols and rifles. One example can be seen in an arms battle with a sheriff named George A. "Bud" Frazer, in which the plate successfully deflects all the bullets from six body shooters.
In 1881, George E. Goodfellow's gravestone doctor noticed that a Charlie Storms faro merchant who was shot twice by Luke Short had a bullet stopped by a silk handkerchief in his breast pocket that prevented the bullet from penetrating. In 1887, he wrote an article entitled Impuletrability of Silk to Bullets for Southern California Practitioners documenting the first known sample of bulletproof material. He experimented with silk vests resembling medieval gambesons, which use 18 to 30 layers of silk cloth to protect the wearer from penetration.
Fr. Kazimierz? used Goodfellow's findings to develop a bulletproof vest made of silk fabric at the end of the 19th century, which could stop the relatively slow spin of black powder gun. The vest cost $ 800 USD each in 1914, a small fortune given the current $ 20.67/1oz-Au exchange rate, equivalent to ~ $ 50,000 in 2016, exceeding the average annual income.
A similar vest, made by Polish inventor Jan Szczepanik in 1901, saved Alfonso XIII's life from Spain when he was shot by an attacker. In 1900, US gangsters wore a $ 800 silk vest to protect themselves.
On June 28, 1914, Archduke Franz Ferdinand of Austria, the heir to the Austria-Hungary throne was shot dead; Despite having a bulletproof vest, which was tested by the British Empire, Armors indicated it was likely to stop the bullet in that era, and despite realizing the potential threat to his life including his uncle's attempted murder a few years earlier, Ferdinand did not wear on that fateful day.
First World War
World War I combatants started a war without trying to provide soldiers with body armor. Various private companies advertise body protective clothing such as Birmingham Chemico Body Shield, although these products are generally too expensive for the average soldier.
The first official attempt at commissioning body armor was made in 1915 by the British Army Design Committee, in particular 'Bomber's Shield' for the use of famous bomber pilots under air protection from anti-aircraft bullets and shrapnel. The Experimental Ordnance Board also reviews potential materials for bulletproof clothing and fragments, such as steel plates. A 'necklet' was successfully expelled on a small scale (due to cost considerations), which protects the neck and shoulders from a bullet that travels at 600 feet per second with a layer of silk and cotton reinforced with resin. Dayfield body armor began operations in 1916 and hardened chest covers were introduced the following year.
The medical service of the British army was counted towards the end of the War, that three quarters of all battle injuries could have been prevented if effective armor had been removed.
France also experimented with a steel visor attached to Adrian's helmet and 'stomach armor' designed by General Adrian. This fails practically, as they severely inhibit the mobility of warriors. Germany officially issued body armor in the form of nickel and silicon steel plates called 'Lobster armor' from late 1916. It is equally too heavy for practical to rank-and-file, but is used by static units, such as guards and sometimes - sometimes the machine-gunner. The improved version, Infantrie-Panzer, was introduced in 1918, with hooks for equipment.
The United States developed several types of body armor, including the steel chrome nickel Brewster Body Shield, which consists of a chest cover and a steel cap and can hold Lewis Gun's bullet at 2,700 feet/s (820 m/s), but is awkward and heavy at  £ 40 (18 kg). An overlapping scale steel scale vest mounted on the skin layer is also designed; This armor weighs 11 pounds (5.0 kg), fits close to the body, and is considered more comfortable.
During the late 1920s and early 1930s, armed men from criminal gangs in the United States began wearing cheaper vests made of thick layers of cotton and cloth. This initial vest can absorb spin gun impacts like.22 Rifle Length,.25 ACP,.32 S & amp; W Long,.32 S & amp; W,.380 ACP,.38 Special and.45 ACP travel at speeds up to 300 m/s (980 ft/s). To deal with this vest, law enforcement agencies like the FBI are starting to use newer and stronger.38 Super, and then.357 Magnum cartridges.
Second World War
In 1940, the UK Medical Research Council proposed the use of light armor for general use by infantry, and heavier clothing for troops in more dangerous positions, such as anti-aircraft and naval crews. In February 1941, trials began on body armor made of manganese steel plates. Two plates cover the front area and one plate on the lower back protects the kidneys and other vital organs. Five thousand sets were made and evaluated almost with unanimous approval - as well as providing adequate protection, the armor did not greatly hinder the mobility of the soldiers and was quite comfortable to wear. The armor was introduced in 1942 even though the demand for it was subsequently scaled down. Canadian troops in northwestern Europe also adopted this armor for medical personnel from the 2nd Canadian Infantry Division.
The British company Wilkinson Sword began producing a bulletproof jacket for a bomber crew in 1943 under a contract with the Royal Air Force. It is realized that the majority of pilot deaths in the air are due to low-speed cuts rather than bullets. The US Army Air Force surgeon, Colonel M. C. Grow, who is stationed in England, thinks that many of his injuries can be prevented by some sort of light armor. Two types of armor are issued for different specifications. These jackets are made of nylon fabric and are able to stop flak and shrapnel, but are not designed to stop bullets. Although they were considered too large for pilots using Avro Lancaster bombers, they were adopted by the United States Air Force Air Force.
In the early stages of World War II, the United States also designed body armor for infantry troops, but most models were too heavy and limited mobility to be useful in the field and did not match the equipment needed. By the middle of 1944, armor development of the infantry body in the United States resumed. Some vests are produced for the US military, including but not limited to T34, T39, T62E1, and M12. The United States developed a vest using Doron Plate, a fiberglass-based laminate. This vest was first used in the Battle of Okinawa in 1945.
The Soviet Armed Forces use several types of body armor, including SN-42 ("Stalnoi Nagrudnik" is Russian for "steel chest", and the number represents the year of design). All tested, but only SN-42 is put into production. It consists of two pressed steel plates that protect the front body and groin. The plate is 2 mm thick and weighs 3.5 kg (7.7 pounds). These armor are generally supplied to SHISBr (attack engineers) and Tankodesantniki. The SN protective armor protects from 9nÆ' 19mm bullets fired by the MP 40 by about 100 meters, and is sometimes capable of deflecting 7.92 Mauser bullets (and bayonet blades), but only at very low angles. That makes it useful in urban battles like the Battle of Stalingrad. However, the weight of SN makes it impractical for infantry in the open.
Postwar
During the Korean War, several new vests were produced for the United States military, including M-1951, which used fiber-reinforced fibers or aluminum segments woven into nylon vests. These vests represent "tremendous weight gain, but the armor failed to stop bullets and debris with great success," although officially they claimed to be able to stop gun pistol Tokarev 7.62ÃÆ'â € "25mm in its snout. Developed by Natick Laboratories and introduced in 1967, the T65-2 plate operators were the first vests designed to withstand hard ceramic plates, enabling them to stop a 7 mm rifle round.
This "Chicken Plate" is made of boron carbide, silicon carbide, or aluminum oxide. They were issued to the crew of low-flying aircraft, such as UH-1 and UC-123, during the Vietnam War.
In 1969, American Body Armor was established and began to produce a patented combination of coated nylon confronted with double steel plates. This armor configuration is marketed to American law enforcement agencies by Smith & amp; Wesson with the trade name "Barrier Vest." Barrier Vest is the first police vest to be used extensively during high-threat police operations.
In 1971, research chemist Stephanie Kwolek discovered a liquid crystalline polymer solution. Its extraordinary strength and rigidity led to the discovery of Kevlar, synthetic fibers, woven into fabric and layered, which, by weight, had five times the tensile strength of steel. In the mid-1970s, DuPont companies employing Kwolek introduced Kevlar. Soon Kevlar was incorporated into the National Institute of Justice's (NIJ) evaluation program to provide light and strong body armor to test a group of American law enforcement officers to ascertain whether daily usage is possible. Lester Shubin, a program manager at NIJ, runs this law enforcement feasibility study in selected large police agencies, and quickly determines that Kevlar's armor can be comfortably worn by police every day, and will save lives.
In 1975 Richard A. Armellino, founder of American Body Armor, marketed all Kevlar vests called K-15, consisting of 15 layers of Kevlar which also included 5 "ÃÆ'â €" 8 "steel balloons" Shok Plate "vertically positioned on top. and issued US Patent # 3,971,072 for this innovation. The same size and positioned "trauma plate" is still used today in the front ballistic panel of the most capable vest, reducing blunt trauma and improving ballistic protection in the heart/sternum center area.
In 1976, Richard Davis, founder of Second Chance Body Armor, designed the company's first all-Kevlar vest, Model Y. The lightweight, launched vest industry was launched and a new form of daily protection for modern police officers was quickly adjusted. In the mid to late 1980s, an estimated 1/3 to 1/2 police patrol officer wore a vest every day. In 2006, more than 2,000 documented "stored" police vests were recorded, validating the efficacy and efficiency of lightweight body armor as part of standard daily police equipment.
Recent years
During the 1980s, the US military issued a PASGT kevlar vest, rated at the IIA level of NIJ, capable of stopping rounds of the gun (including 9 mm FMJ) and fragmentation. West Germany issued a similar identification vest called Splitterschutzweste.
The Kevlar soft armor has its drawbacks because if "large pieces or high-speed bullets hit the vest, energy can cause life-threatening trauma injuries" in the selected and vital areas. Ranger Body Armor was developed for the American military in 1991. Although it is a second modern American body armor capable of stopping rounds of rifle caliber and still light enough to be worn by infantrymen in the field, it still has its drawbacks: "It's still heavier than the anti coupling -fragmentation used by regular infantry forces and... not having the same level of ballistic protection around the neck and shoulders. " The Ranger Body Armor format (and newer body armor issued for US special operations units) highlights the trade-off between strength and mobility protection that should be handled by modern armor bodies.
The new armor issued by the United States armed forces for a large number of troops includes an Enhanced Overseas Tactical Vest from the US Army and US Marine Corps Modular Tactical Vests. All these systems are designed with vests that are intended to provide protection from cut and pistol rotation. Harder ceramic plates, such as the Protective Small Arms Weapons, such as those used with Interceptor Body Armor, are used to protect vital organs from higher level threats. These threats are mostly high speed and riffle riffle armor-piercing. This type of similar protection equipment has been adopted by the modern armed forces in the world.
Since the 1970s, several new fibers and construction methods for bulletproof fabrics have been developed in addition to Kevlar weavings, such as Dyneema DSM, Flex Gold Honeywell and Spectra, Twinon's Teijin Aramid, Pinnacle Armor's Dragon Skin, and Zogo Toyobo. The US military has developed a body armor for worker dogs that help GIs in combat.
Since 2004, the US Special Operations Command has been working on new body armor that will rely on rheology, or the technology behind liquid elasticity in skin care and automotive products. Named TALOS, this new technology can be used in the future.
Maps Bulletproof vest
Performance standards
Due to various types of projectiles, it is often inaccurate to refer to a particular product as "bulletproof" because it implies that it will protect against any and all threats. In contrast, the term bulletproof is usually preferred.
Standard body armor is regional. Around the world ammunition varies and as a result armor testing should reflect locally found threats. Law enforcement statistics show that many shootings where officers were injured or killed involved officer's own weapons. As a result, any law enforcement agency or para-military organization will have their own standards for armor performance if only to ensure that their armor protects them from their own weapons. While many standards exist, some standards are widely used as models. The ballistics and puncture documents of the US National Justice Institute are examples of widely accepted standards. In addition to NIJ, the UK Home Office Scientific Development Branch (HOSDB - formerly the Scientific Branch Development Standard of the Police (PSDB)) is used by a number of other countries and organizations. This "model" standard is usually adapted by other countries by incorporating a basic test methodology with bullet modification required for testing. NIJ Standard-0101.06 has a specific performance standard for bulletproof vests used by law enforcement. This figure supports the following scale of penetration and also the protection of blunt trauma (deformation): In the first half of 2018, NIJ is expected to introduce a new NIJ Standard-0101.07. This new standard will completely replace NIJ Standard-0101.06. The current system uses Roman numerals (II, IIIA, III, and IV) to indicate the threat level will be lost and replaced by naming conventions similar to the standards developed by the UK Home Office Scientific Development Branch. HG for soft armor and RF for hard armor. Another important change is the speed of the test round for the conditioned armor will be the same as the new armor during the test. For example, for NIJ Standard-0101.06 Level IIIA, round 44. The magnum is currently shot at 408 m/s for the air-conditioned armor and at 436 m/s for the new armor. For NIJ Standard-0101.07, the speed for new and conditioned armor will be the same.
Standard NIJ is used for law enforcement armors. Military armor designs of US and NATO were tested using a set of standard test methods under ARMY MIL-STD-662F and STANAG 2920 Ed2. This approach defines testing processes below the 662F/2920 standard. Each armor program can select a unique set of projectiles and speeds as needed. The DOD and MOD armor program-of-record (MTV for example) get armor using these test standards. In addition, special requirements may be defined under this process for armors for flexible rifle protection, fragment protection for extremities, etc. This military procurement requirement is not related to NIJ, HOSDB or ISO law enforcement standard, test method, garment size, projectile or speed.
In addition to NIJ and HOSDB law enforcement standards, other important standards include German Police TR-Technische Richtlinie, ISO Design pren ISO 14876, and Underwriters Laboratories (UL Standard 752).
Textile armor is tested for both penetration resistance with bullets and for impact energy transmitted to the wearer. "Rear signatures", or transmitted collision energies, are measured by armor shots mounted in front of supporting materials, usually oil-based modeling clays. Clay is used at controlled and verified temperatures for the impact stream prior to testing. After the armor is exposed to a test bullet, the vest is removed from the clay and the indentation depth in the clay is measured.
The back signatures allowed by different test standards can be difficult to compare. Both clay and bullet materials used for the tests are not common. In general, other British, German and European standards allow a 20-25 mm backface signature, while the US-NIJ standard allows for 44 mm, potentially causing internal injury. The allowable backface signature for body armor has been a controversy since it was introduced in the first NIJ test standards and the debate over the relative importance of penetration resistance vs the backface signature continues in the medical community and testing.
Generally the textile material of the vest is temporarily degraded when wet. Neutral water at room temperature does not affect para-aramid or UHMWPE but acidic, basic and some other solutions may permanently reduce the tensile strength of para-aramid fibers. (As a result of this, the main test standard calls for wet testing of textile armor.) The mechanism for loss of wet performance is unknown. The vests to be tested after ISO type soaking tend to have a hot enclosed enclosure and which are tested by NIJ type water spraying methods tend to have a waterproof sheath.
From 2003 to 2005, a major study on the environmental degradation of Zylon armor was carried out by the US-NIJ. It concludes that water, long-term use, and temperature exposure significantly affect tensile strength and ballistic performance of PBO or Zylon fiber. The NIJ study of back vests from the field shows that the environmental effects on Zylon result in ballistic failure under standard test conditions.
Ballistic Testing V50 and V0
Measuring ballistic performance of armor is based on determining the kinetic energy of the bullet during impact ( E k Ã, = ½ mv < soup> 2 ). Since bullet energy is a key factor in penetration capacity, speed is used as the main independent variable in ballistic testing. For most users the key measurement is the speed at which no bullets will penetrate the armor. Measuring this zero penetration rate ( v 0 ) should take into account the variability in armor performance and test variability. Ballistic testing has a number of sources of variability: armor, supporting test materials, bullets, casing, powder, primer and gun barrel, to name a few.
Variability reduces the predictive power of the determination of V0. If for example, the v 0 of the armor design is measured to be 1,600 ft/s (490 m/s) with a 9 mm FMJ bulb based on 30 shots, this test is only a real estimate > v 0 of this armor. The problem is variability. If v 0 is tested again with the second group of 30 shots on the same vest design, the result will not be the same.
Only one single low-speed translucent shot is required to reduce the value v 0 . The more shots being made lower v 0 will go away. In terms of statistics, the zero penetration speed is the tail end of the distribution curve. If variability is known and the standard deviation can be calculated, one can strictly adjust V0 at the confidence interval. The test standard now determines how many images should be used to estimate v 0 for armor certification. This procedure defines the estimated confidence interval v 0 . (See "NIJ and HOSDB testing methods".)
v 0 is difficult to measure, so a second concept has been developed in ballistics testing called the ballistic limit ( v 50 ). This is the speed at which 50 percent of shots penetrate and 50 percent are stopped by the armor. US military standard MIL-STD-662F V50 Ballistics Test determines commonly used procedures for this measurement. The goal is to get three shots that penetrate the slower of the second group faster than three shots that are stopped by the armor. These three high stops and three low penetrations can then be used to calculate v 50 velocity.
In practice these measurements v 50 require 1-2 vest panels and 10-20 shots. A very useful concept in armor testing is the offset velocity between v 0 and v 50 . If this offset has been measured for armor design, then v 50 data can be used to measure and estimate changes in v 0 . For vest making, field evaluation and live test both v 0 and v 50 are used. However, as a result of the simplicity of making v 50 measurements, this method is more important to control armor after certification.
Military_testing: _fragment_ballistics "> Military testing: ballistic fragments
After the Vietnam War, military planners developed the concept of "Casualty Reduction". The massive bodies of victim data make it clear that in combat situations, fragments, not bullets, are the most important threat to the army. After World War II, vests were being developed and fragment testing was at an early stage. Artillery shells, mortars, air bombs, grenades, and antipersonnel mines are all fragmentation devices. They all contain steel casing that is designed to explode into small pieces of steel or shrapnel, when their explosive nucleus explodes. After considerable effort measuring the size distribution of fragments from various NATO and Soviet bloc munitions, fragment tests were developed. The fragment simulator is designed, and the most common form is the right circular cylinder or RCC simulator. This shape has the same length as its diameter. The RCC Fragment Simulation Project (FSP) was tested as a group. The most frequent series of tests included 2 grains (0.13 g), 4 grains (0.263 g), 16 grains (1.0 g), and 64 grains (4.2 g) RCC FSP mass testing. Series 2-4-16-64 is based on measured fragment size distribution.
The second part of the "Reduction Reduction" strategy is the study of the speed distribution of pieces of ammunition. Warhead explosives have a blast velocity of 20,000 ft/s (6,100 m/s) up to 30,000 ft/s (9,100 m/s). As a result, they were able to extract fragments at very high speeds over 3,300 ft/s (1,000 m/s), implying very high energies (where energy fragments are ½ mass ÃÆ'â € "sup 2 , ignoring energy rotation). Military engineering data show that, like the size of fragments, fragment speeds have characteristic distributions. It is possible to segment the fragment output from the warhead into the speed group. For example, 95% of all fragments of a bomb explosion under 4 grains (0.26 g) have a speed of 3,000 ft/sec (910 m/s) or less. It sets a set of goals for the design of military ballistic vests.
The random nature of fragmentation requires the specifications of military vests to trade mass vs. ballistic gains. Armor vehicles are able to stop all fragments, but military personnel can only carry equipment and supplies in limited quantities, so the weight of the vest is a limiting factor in the protection of the vest fragments. Grain series 2-4-16-64 with limited speed can be stopped by the vest of all textiles around 5.4 kg/m 2 (1,1Ã, lb/leg 2 ). Unlike the vest design to lead a shapeless bullet, the fragment does not change shape; they are steel and can not be deformed by textile materials. The 2-grains (0.13 g) FSP (the smallest fragment projectile commonly used in testing) is about the size of a grain of rice; such fast moving small fragments could potentially pierce the vest, moving between the threads. As a result, fabrics optimized for fragment protection are welded closely, although the fabric is ineffective in stopping tin cartridges.
Backing up material for testing
Ballistics
One important requirement in soft ballistic testing is the measurement of "back side signatures" (ie energy delivered to the network by unbroken projectiles) in a shapeshifted support material placed behind the targeted vest. The majority of military standards and law enforcement have been settled on a mixture of oil/clay for supporting materials, known as Roma Plastilena. Although harder and less deformable than human tissue, Rome is the "worst case" backing material when plastic deformation in oil/clay is low (less than 20 mm). (Armor placed on a harder surface is more easily penetrated.) The "Romanian" oil/clay mixture is approximately twice the density of human tissue and therefore does not correspond to its specific gravity, but "Rome" is a plastic material that will not recover its shape is elastically, which is essential for accurately measuring potential trauma through the back signature.
Selection of test support is essential because in flexible armor, the wearer's tissue plays an integral part in absorbing the high-energy impact of ballistic events and punctures. But the human body has very complex mechanical behavior. Away from the ribs and spine, soft-tissue behavior is soft and submissive. In the tissues above the region of the sternal bone, the adherence of the torso is significantly lower. This complexity requires a very detailed system of bio-morphic support materials for accurate ballistic testing and armor puncture. A number of materials have been used to simulate human tissue in addition to Rome. In all cases, these materials are placed behind the armor during the impact test and are designed to simulate various aspects of human tissue impact behavior.
One important factor in support testing for armor is its hardness. Armor is more easily penetrated in testing when supported by harder material, and hence tougher material, such as Roman clay, is a more conservative test method.
Stab
Standard stab and spike armor have been developed using 3 different support materials. The draft EU norm calls clay Rome, California DOC calls 60% ballistic gelatin and the current standard for NIJ and HOSDB calls multi-part foam and rubber material.
- Using Roman clay support, only a metallic thrust solution that fills 109 joules of Calif. DOC ice pick requirement
- Using 10% Gelatin backing, all fabric puncture solutions are able to meet 109 joules Calif. DOC ice pick requirement.
- Recently the ISO draft PREN ISO 14876 chose Rome as a support for ballistics and stab test.
This history helps explain important factors in ballistic testing and Stab armor, supporting the rigidity affecting the penetration resistance of armor. The energy loss of the armor-tissue system is Energy = Force ÃÆ'â € "Displacement when testing on a softer and more deformable backing energy total impact energy is absorbed at lower forces. When the force is reduced with a softer, soft support, the armor will not be penetrated. The more rigorous use of Roman material in ISO design norms makes this the most stringent stab standard currently in use.
Armor resistant gun
Due to technological limitations, differences are made between gun protection and rifle protection. See level 3 and 4 NIJs for general requirements for armor resistant armor. Armor resistant armor is broadly composed of three basic types: ceramic base plate system, steel plate with spill fragmentation protection layer, and hard fiber-based lamination system. Many of the rifle armor components contain hard ceramic components and laminated textile materials used together. Various types of ceramic materials are being used, however: aluminum oxide, boron carbide and silicon carbide are the most common. The fibers used in this system are similar to those found in soft textile armor. However, for rifle protection, high-pressure polyethylene laminates with very high molecular weight with the Kraton matrix are the most common.
Small Arms Weapon Inserts (SAPI) and enhanced SAPI plates for US DOD generally have this form. Due to the use of ceramic plates for rifle protection, these vests are 5-8 times heavier on the base area as gun protection. The weight and rigidity of armor rifles is a major technical challenge. Density, hardness and impact toughness are one of the balanced material properties for designing this system. While ceramic materials have some remarkable properties for ballistics they have poor fracture toughness. Failure of ceramic plates with cracks should also be controlled. For this reason, many ceramic gun plates are composite. The hammer face is a ceramic with a backface formed of laminated fibers and resin materials. Ceramic hardness prevents bullet penetration while the tensile strength of fiber support helps prevent pull failure. Examples of rifle-resistant outer vests include body armor Interceptor and Improved Outer Tactical Vest.
Versus ammunition breaking armor
The standard for armor-piercing rifle bullets is unclear, because bullet penetration depends on the hardness of the target armor. However, there are some general rules. For example, bullets with soft lead-core and copper jackets are too easily deformed to penetrate hard materials, whereas rifle bullets made with very hard core materials, such as tungsten carbide, are designed for maximum penetration into hard armor. Most other core materials will have an effect between lead and tungsten carbide. Many common bullets, such as standard M29 bullets 7.62 × 39mm for AK-47 rifles, have steel cores with hardness ratings ranging from mild steel Rc35 to medium hard steel Rc45.
In addition, as the bullet core hardness increases, so does the amount of ceramic coating used to stop penetration. As in soft ballistics, the hardness of the minimum ceramic material from the bullet core is required to damage each of its hard core material, but in the armor piercing round, the bullet core is eroded rather than defective.
The US Department of Defense uses two protection classes from armor penetrating armor rifles. First, the Protective Small Arm (SAPI), called a ceramic composite plate with a mass of 20-30 kg/m 2 (4-5 pounds/leg 2 ). Then, the enhanced SAPI (ESAPI) specification was developed to protect against more penetrating ammunition. The ESAPI ceramic plate has a density of 35-45 kg/m 2 (7-9 liters), and is designed to stop bullets such as.30-06 AP (M2) with engineered hard core.
Cercom, now BAE systems, CoorsTek, Ceradyne, TenCate Advanced Composites, Honeywell, DSM, Pinnacle Armor and a number of other engineering companies develop and produce materials for rifle ceramic composite armor.
Explosive protection
Bomb bombers often wear heavy armor designed to protect from most moderate-sized explosive effects, such as bombs encountered in terror threats. Full head helmet, covering the face and some level of protection for the limbs is mandatory in addition to a very strong armor for the body. Inserts to protect the spine are usually applied to the back, if there is an explosion of the wearer. The visibility and mobility of the wearer is very limited, such as the time that can be spent working on the device. Armor designed primarily to fight explosives is often somewhat less effective against bullets than armor designed for that purpose. The most mass of bomb-destroying equipment usually provides some protection, and the bullet-specific trauma plate is compatible with some bomb disposal suits. Disposal technicians attempt to complete their tasks if possible using remote methods (eg, robots, lines and pulleys). Actually putting a hand on a bomb is only done in a very life-threatening situation, where danger to people and critical structures can not be reduced by using wheeled robots or other techniques.
Stab and stab-ballistic armor
Initial test "ice pick"
In the mid-1980s the state of California Department of Corrections issued a requirement for body armor using commercial pick es as a test penetrator. A test method to simulate the human attacker's ability to energize collisions with the upper body. As demonstrated by the work of the former British PSDB, this test is more than stating the capacity of human attackers. This test uses a falling mass or a sabot that carries an ice breaker. Using the force of gravity, the height of the mass falls on the vest is proportional to the energy of the collision. The test assigned 109 joules (81Ã, ftÃ,  · lb) of energy and a mass drop of 7.3 kg (16Ã,½) with a high drop of 153 153 cm (60Ã, in).
Ice pick has a diameter of 4 mm (0.16 inches) with a sharp tip with a terminal speed of 5.4 m/s (17 ft/sec) in testing. The California standard does not include a knife or sharp weapon in the test protocol. Test method using oil/clay (Rome Plastilena) simulant network as a support test. In this early phase only the supply of titanium and steel plates that successfully handle this requirement. Point Blank developed the first ice certified offerings for CA Department of Corrections in the form of titanium metal sheets. This type of vest is still used in US correction facilities in 2008.
Beginning in the early 1990s, an optional test method was approved by California that allowed the use of 10% ballistic gelatin as a substitute for Roman clay. The transition from Rome's ground-based solid, hard to soft gelatin low-density allows all textile solutions to meet the energy needs of this attack. All soft textile "ice pick vests" were adopted by California and other US states as a result of this migration in testing methods. It is important for the user to understand that the smooth and rounded edge of the ice does not cut the fiber on impact and this allows the use of textile-based vests for this application.
The earliest of these "all" cloth vests designed to overcome this ice pick test is the ultra-strong TurtleSkin woven para-aramid fabric from Warwick Mills with a patent filed in 1993. Shortly after TurtleSkin's work, in 1995 DuPont patented the fabric medium density designated as Kevlar Correctional. It should be noted that these textile materials are not performing equally with leading threats and these certifications are only with ice breakers and not tested with a knife.
Standard HOSDB-Stab and Slash
In line with the US development of the "ice pick" vest, British police, PSDB, are working on a standard for blade-resistant body armor. Their program adopts a rigorous scientific approach and collects data on the capacity of human attacks. Their ergonomic studies suggest three levels of threat: 25, 35 and 45 joules of impact energy. In addition to the impact of an energy attack, the speed is measured and found to be 10-20 m/s (much faster than the California test). Two commercial blades are selected for use in this PSDB test method. To test the velocity of representation, an air cannon method was developed to move the blade and sabotage the vest target using compressed air. In this first version, the PSDB '93 test also uses oil/clay materials as a simulant network support. The introduction of fiber-cut blades and harsh tests supports pocket vest manufacturers to use metal components in their vest design to address these more stringent standards. Current Standard Armored Body Armor HOSDB for British Police (2007) Section 3: Knives and Spike Resistance are aligned with the US NIJ OO15 standard, using fall test methods and using composite foam backing as a network simulant. Both HOSDB and NIJ tests now define engineered blades, two-edged S1 and single-end P1 as well as spikes.
In addition to puncture standards, HOSDB has developed a standard for slash endurance (2006). This standard, such as the puncture standard, is based on a test assay with a test blade in controlled mass installation. The slash test uses a Stanley Utility knife or a box cutter blade. Standard slashes test the cut resistance of the armor panel parallel to the direction of the blade travel. The test tool measures the instantaneous force of the tip of the blade producing a sustainable slash through the vest. These criteria require that the failure of armor slashes be greater than 80 newton styles.
Bow and spherical ballistic vest
The vest that combines stabbing and ballistic protection is a significant innovation during the 1990's vest development period. The starting point for this development was the ballistic-only offering at that time using NIJ Level 2A, 2 and 3A or HOSDB HG 1 and 2, with a ballistic composite ballistic product manufactured with an area density between 5.5 and 6 kg/m² (1 , 1 and 1.2 lb/ftÃ,² or 18 and 20 oz/ftÃ,²). But police forces evaluate their "street threats" and require vests with knives and ballistic protection. This multi-threat approach is common in the United Kingdom and other European countries and is less popular in the US. Unfortunately for multi-threat users, the metal arrangement and the chainmail system needed to defeat the test bar offer little ballistic performance. The multi-threat vest has an area density close to the sum of two solutions separately. This vest has a mass value in the range of 7.5-8.5 kg/m² (1.55-1.75 pounds/ftÃ,²). Ref (list of NIJ and HOSDB certifications). Rolls Royce Composites -Megit and Highmark produce a metallic system to meet this HOSDB standard. This design is used extensively by the London Metropolitan Police Service and other institutions in the UK.
US and English standard update
When the producing vest and determining authority are working with this standard, the English and US Standard teams begin collaboration on the test method. A number of problems with the first version of the test need to be addressed. The use of commercial blades with inconsistent sharpness and tip shape creates problems with test consistency. As a result, two newly designed "engineering knives" can be produced to have reproducible translucent behavior. Simulants tissue, Roman clay and gelatin, do not represent tissue or are not practical for test operators. Backing composite test-foam and hard rubber was developed as an alternative to overcome this problem. The fall test method is selected as the baseline for the updated standard above the air cannon option. The decrease in mass decreases from "ice picking tests" and soft relationships such as wrists are engineered into sabot-penetrators to create more realistic test impacts. These closely related standards were first issued in 2003 as HOSDB 2003 and NIJ 0015. (The Police Scientific Development Branch (PSDB) was renamed the Office of Scientific Development of the Home Office in 2004.)
Stab and spike vests
This new standard creates a focus on Level 1 on 25 joules (18Ã, ft? Lbf), Level 2 at 35Ã, J (26Ã, ft? Lbf), Level 3 on protection 45Ã, J (33Ã, ft? Lbf) as tested with New engineering blades are defined in this test document. The lowest level of this requirement at 25 joules is handled by a series of textile products from both wovens, coated wovens and laminated woven materials. All of these ingredients are based on Para-aramid fibers. The friction coefficient for ultra high molecular weight polyethylene (UHMWPE) prevents its use in this application. The TurtleSkin DiamondCoat and Twaron SRM products address this requirement using a combination of Para-Aramid wovens and tied ceramic grains. These ceramic coated products do not have the flexibility and softness of uncoated textile materials.
For higher protection rates, L2 and L3, the highly aggressive penetration of small and thin P1 blades has resulted in the continuous use of metal components in the puncture guard. In Germany, Mehler Vario Systems develops para-aramid and chainmail hybrids, and their solutions are selected by the London Metropolitan Police Service. BSST another German company, in collaboration with Warwick Mills, has developed a system to meet the puncture-ballistic requirements using Dyneema laminate and the advanced metal-array system, TurtleSkin MFA. This system is currently implemented in the Netherlands. Trends in multi-threat armor are continuing with requirements for needle protection in ISO draft pren ISO 14876 norms. In many countries there is also an interest to combine the protection of military-style explosive fragmentation with ballistic bullets and puncture requirements.
Size vest, introduction and encapsulation
In order for ballistic protection to be used, ballistic panels and hard-resistant rifle plates are installed inside special carriers. The carrier is the visible part of the ballistic vest. The most basic carriers include pockets that hold the ballistic panel and strap to install the carrier to the user. There are two main types of carriers: military or tactical carrier worn over the shirts, and the type of law enforcement imposed under the shirts.
Military operators
The type of military carrier, British waist waist carrier, or tactical police carrier usually has a series of net connectors, hooks, and loops, on the front and rear. This allows the user to install various equipment to the carrier in various configurations. This load-carrying feature is an essential part of uniform and operational design for police and military weapons teams.
In addition to load carrying, this type of carrier may include pockets for neck protectors, side plates, groin plates, and rear protection. Because these carrier styles do not match, the size in this system is very easy for men and women, making custom fabrication unnecessary.
Hidden operator
Law enforcement operators in some countries are hidden. The bearer holds a ballistic panel close to the wearer's body and a uniform shirt worn over the operator. This carrier type should be designed to fit the officer's body shape. For armor that can be disguised to fit the body, it must be mounted correctly to a specific individual. Many programs specify specific measurements and the manufacture of armor panels and carriers to ensure fit and comfortable armor. Officers who are either female or significantly overweight have more difficulty in measuring accurately and have comfortable armor made.
Vest slip
A third textile layer is often found between the carrier and the ballistic component. Ballistic panels lined with pouch or skid coated. This slip provides ballistic material encapsulation. Slips are produced in two types: sealed airtight slip and simple sewn slip. For some ballistic fibers such as Kevlar slip is an important part of the system. This skid prevents moisture from the user's body from saturating the ballistic material. Protection from this moist cycling increases the useful life of armor.
Research
Progress in fiber mathematics
In recent years, advances in materials science have opened the door to the idea of ​​a literal "bulletproof vest" capable of stopping gun and gun rifles with soft textile vests, without the aid of additional metal or ceramic coatings. However, progress is moving at a slower rate than other technical disciplines. The latest offering from Kevlar, Protera, was released in 1996. The current soft body armor can stop most of the pistol's revolutions (which have been going on for about 15 years), but armor plates are required to stop the rounds of shotguns and rounds of core-steel rifles such as 7, 62ÃÆ' â € "25mm. Para-aramid has not developed beyond the 23 gram per denier limit in fiber persistence.
Improved simple ballistic performance has been performed by new manufacturers of this type of fiber. The same can be said for UHMWPE materials; the basic fiber properties only advance to the range 30-35 g/d. Improvements in this material have been seen in the development of crossed non-woven laminates, such as Spectra Shield. The major ballistic performance of PBO fiber is known as the "warning story" in materials science. This fiber allows the design of soft armor weapons that are 30-50% lower than aramid and UHMWPE materials. However, this higher ductility is delivered with a weakness in well-publicized environmental durability.
The Akzo-Magellan team (now DuPont) has worked on fibers called M5 fibers; However, the startup announced from its pilot plant has been delayed for more than 2 years. The data show that if M5 material can be brought to the market, its performance will be approximately equivalent to the PBO. In May 2008, Teijin Aramid group announced a "super fiber" development program. Teijin's emphasis appears to be on computational chemistry to determine solutions for high ductility without environmental weakness.
Material science of second generation "super" fibers is complex, requires substantial investment, and is a significant technical challenge. The study aims to develop artificial spider silk that can be super strong, yet light and flexible. Other research has been done to utilize nanotechnology to help create super strong fibers that can be used in future bulletproof vests.
Textile wovens and lamination research
Finer threads and lighter weaving fabrics have been a key factor in improving ballistic outcomes. The cost of ballistic fiber rises dramatically as the yarn diminishes, making it unclear how long this trend can continue. The current practical limit of fiber size is 200 denier with most wovens limited to 400 denier levels. The three-dimensional weave with fiber connecting the flat wovens together into the 3D system is being considered for both hard and soft ballistics. Team Engineering Inc. is designing and weaving this multi layer material. Dyneema DSM has developed higher performance laminates using fiber, the new higher power designated SB61, and HB51. DSM feels this advanced material provides some performance improvements, but SB61's "soft ballistic" version has been pulled back. On Show Shot in 2008, a unique composite of interlocking steel plates and soft UHWMPE plates exhibited by TurtleSkin. In combination with more traditional woven fabrics and laminates a number of research efforts work with ballistic brushes. Tex Tech has been working on these materials. Like 3D weaving, Tex Tech sees advantages in the 3-axis fiber orientation.
Fiber is used
Ballistic nylon (up to 1970) or Kevlar, Twaron or Spectra (competitor for Kevlar) or polyethylene fiber can be used to produce bulletproof vests. The vest at that moment is made of ballistic nylon & amp; equipped with glass-fiber plate, steel, ceramic, titanium, doron & amp; composite ceramics and fiberglass, the latter is the most effective.
Manufacturing process
A. Making fabric panel- 1. To make Kevlar fabric, Kevlar yarn is woven in the simplest pattern, plain weave or tabby. which is merely an advantage & amp; under alternating thread pattern or. 2. Unlike Kevlar, Spectra used in bulletproof vests is usually not woven. otherwise a strong polyethylene polymer filament is spun into fibers which are then placed parallel to each other. Resin is used to coat the fibers, sealing them together to form a piece of Spectra cloth. Two pieces of cloth are then placed at right angles to each other and again bonded, forming a nonwoven fabric which is then flanked between two sheets of polyethelene film. The shape of the vest can then be cut from the material.
b. Cutting panel-
C. Sewing Ballistic Panels -
d. Completed the Shells for panel stitched together in the same industry standard sewing machine and standard sewing practice. Panels are then tucked into shells and accessories - like straps - sewn. The bulletproof vest that has been packed and shipped to the customer.
Working principle
When a hand gun bullet strikes the body armor, it is captured in a very strong "fiber net". These fibers absorb and dissolve the collision energy that is transmitted to bulletproof vests from bullets that cause the bullet to change shape, otherwise known as "mushroom". The additional energy is absorbed by each successive layer or material in a bulletproof vest until the time of the bullet has been stopped.
Ceramic plates work by destroying locally where the projectiles attack, and are capable of spreading the projectile energy to the point where the bullets have stopped. Unfortunately, this means the ceramic plate becomes less and less capable of stopping additional bullets, and may not be usable after a number of hits have been taken.
Developments in ceramic armor
Ceramic materials, materials processing and advances in ceramic penetration mechanisms are significant areas of academic and industrial activity. The combined field of ceramic armor research is extensive and may be well summarized by The American Ceramics Society. ACerS has been running an annual armored conference for several years and drafted the 2004-2007 trial. Special activity area associated with the vest is the emergence of small ceramic components. Large-sized torso plates are complex for producing and subject to crack use. The monolithic plate also has a limited multi-hit capacity as a result of large impact fracture zones. This is the motivation for this new type of steel plate. The new design uses two-and three-dimensional ceramic elements that can be rigid, flexible or semi-flexible. The Dragon Skin body armor is one of these systems. European developments in spherical and hexagonal arrangements have resulted in products that have bending and multi-hit performance. Creating an array type system with flexible, consistent ballistic performance on the edge of ceramic elements is an active area of ​​research. In addition, the advanced ceramic processing techniques require an adhesive assembly method. One of the new approaches is the use of hook and loop fasteners to assemble the ceramic arrangement.
Nanomaterials in ballistics
Currently, there are a number of methods by which nanomaterial is being implemented into the body's protective production. The first, developed at the University of Delaware is based on nanoparticles in a suit that becomes rigid enough to protect the wearer as soon as the kinetic energy threshold is exceeded. This coating has been described as a shear thickener. These nano-infused fabrics have been licensed by the BAE system, but by mid-2008, no products were released based on this technology.
In 2005 an Israeli company, ApNano, developed a material that was always rigid. It has been announced that this nanocomposite based on tungsten disulfide nanotubes is able to withstand shocks produced by steel projectiles that travel at speeds of up to 1.5 km/sec. This material is also reported to be able to withstand the shock pressure generated by other impacts of up to 250 metric tons-force per square centimeter (24.5 gigapascals; 3,550,000 psi). During the test, the material proved to be so strong that after the impact it was basically still not tarnished. In addition, a study in France tested the material under isostatic pressure and found it to be stable to at least 350 tf/cmÃ,² (34 GPa; 5,000,000 psi).
In mid 2008, spider silk vest bullet and nano-based armor were being developed for potential market releases. Both the British and American military have expressed interest in carbon fibers being woven from carbon nanotubes developed at the University of Cambridge and have the potential to be used as body armor. In 2008, large format carbon nanotube sheets began to be produced in Nanocomp.
Graphene composite
By the end of 2014, researchers begin studying and testing graphene seb
Source of the article : Wikipedia
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