User:Ewodzanowski/sandbox

History

Between 1971 and 1976, more than $3 million of The National Institute of Justice funds were devoted to the development of Kevlar body armor. The development of body armor by the NIJ was a four-phase effort that took place over several years. They found that the vests could stop the most common lead bullets: 38 Specials and 22 Long Rifle Bullets. A final phase of testing monitored Kevlar armor’s effectiveness. Kevlar armor was found to ensure a 95% probability of survival after being hit with a .38 caliber bullet at a velocity of 800 ft/second. The probability of requiring surgery after being hit by a projectile was found to be 10% or less. Since then, Kevlar laboratories across the country are still continuously developing new technology to address the evolving protective requirements of the military, police and security markets the world over.

Production

Kevlar production is expensive because of the difficulties arising from using concentrated sulphuric acid, needed to keep the water-insoluble polymer in solution during its synthesis and spinning.

Structure and properties

Kevlar is mainly used for two reasons, and both are about performance: It’s lightweight and easy to integrate.

Applications

Armor

Pieces of a Kevlar helmet used to help absorb the blast of a grenade

Americans serving in every branch of the Armed forces since the 1970s have depended upon body armor and flak jackets made with Kevlar to help protect them from combat hazards, such as ballistic projectiles and explosive fragmentation.

Military helmets made with Kevlar meet demanding requirements for protection against a wide range of threats, including bullets, shrapnel and fragmentation.State-of-the-art military helmets made with Kevlar, like the U.S. Army Advanced Combat Helmet, absorb 20% more kinetic energy than the Personnel Armor System for Ground Troops (PASGT) military helmets they are replacing, and offer protection from submachine gun bullets.

Automotive Uses

Pieces of a Kevlar helmet used to help absorb the blast of a grenade

Kevlar helps improves the safety, performance and durability of automotive components for a wide variety of vehicles, from passenger cars and light trucks to professional race cars. It is not uncommon for a new vehicle to have several crucial parts that employ products made of Kevlar brand fibre. Modern racing cars contain Kevlar-reinforced fuel tanks. The high tensile strength of Kevlar makes the fuel tanks inherently difficult to puncture in this case of an accident. This largely eliminated the risk of fire in a crash. These tanks are also very flexible and lightweight; this makes them easy to fit into confined spaces within the vehicle.

Parachutes

Kevlar suspension lines have been used in a wide variety of parachute systems, replacing previous nylons ropes for improved safety.

Spacesuits

The final layer is composed of three fabrics that each serve their own purpose. Kevlar makes up one of the layers and serves as a general purpose protective layer.

Spacecraft

Kevlar fiber has proven that it is strong enough to survive the extreme forces and temperature fluctuations of space travel. When the Mars Pathfinder landed on the surface of Mars, Kevlar® fiber reinforced the inflatable landing cushions – and the ropes that secured them.

Smartphones

The Motorola RAZR Family, the Motorola Droid Maxx, and the OnePlus 2 have a Kevlar backplate, chosen over other materials such as carbon fiber due to its resilience and lack of interference with signal transmission. According to Moto, the unibody Kevlar shell makes it thinner (7.18mm) yet stronger than its predecessors.

Maritime Vessels

Bulkheads, fixed walls, and other interior structures on U.S. Navy and Coast Guard ships sometimes use Kevlar honeycombs to help save weight and mitigate the inevitable corrosion that comes from exposure to sea spray. It is also used in ferries, hydrofoil designs, and recreational boats.

Sports

Terrain Sports

Ski and snowboard manufacturers use Kevlar as a construction material to help increase board stability, reduce chatter (vibration), and keep weight down. In skateboards, Kevlar helps decks retain their “pop” longer and resist breaking. Surfboards incorporate Kevlar for lightweight impact and abrasion resistance.

Hockey

Many ice and field hockey players opt for reinforced sticks made of Kevlar because they help them be lightweight and retain their shape better than fiberglass or wood. When a stick breaks, Kevlar helps prevents a sharp break that can injure another player.

Racquet Sports

Tennis, racquetball, squash, and badminton racquets with Kevlar construction resist cracking and shattering. Strings of Kevlar® don’t stretch as much as conventional strings, and break less frequently. Kevlar is also incorporated for vibration-damping purposes and to help protect the carbon fiber, the leading reinforcement for lightweight ultra-rigid tennis rackets, against damage.

Music

Audio equipment

Kevlar drivers have often been attributed with a slightly richer sound by many professional and amateur listeners. With circumferential variations in stiffness, the cone will have slight variations in the uniformity of sound radiation with the more flexible areas lagging the stiffer areas.