Bulletproof Vest

Bulletproof Vest is the armor that protector for the body such as the chest, abdomen, and back of the person wearing it from a bullet and fragments of a grenade explosion. Commonly used by military personnel and people who have a risk of fire.

Kinds of Bulletproof Vest:
Bulletproof vests are divided into two types, ie Soft and Hard Body Armor Body Armor.
a. Soft body armor

Soft body armor is bullet proof vests made of aramid fibers (aramid fibers). A Kevlar layer thickness of less than 1 mm, generally standard outfit consists of up to 32 layers and weighs up to 10 kg ordinary. These vests tend to be lighter so advantageous for use in tasks disguise, or security for intelligence personnel.

b. Hard Body armor

By adding a layer of soft body armor in particular, can be produced bulletproof vest hard body armor. Generally, a layer made of ceramic (Al2O3 "Alumina"), a slab of metal or composite. The form is thick and heavy make no comfort, until rarely worn in daily tasks. Only in special high-risk tasks, such as military operations or operations SWAT team who will wear the hard body armor.

Material for bulletproof vests

The material used to make bulletproof vests have always been progressing as the results of new discoveries. In general, the materials used are:

a. Aramid (Kevlar)

Kevlar

Aramid Molecular

This material was found by Stephanie Kwolek in 1964, an American chemist, who worked as a researcher at DuPont company. Aramid is the acronym of the word aromatic polyamide. Aramid has a structure strong, tough (tough), has good damping properties (vibration damping), resistant to acid (acid) and bases (leach), but it can withstand heat up to 370 ° C, so it is not flammable.
Products are marketed known as Kevlar. Kevlar has a light weight, but five times stronger than steel.

b. Vestran

Vestran

Vestran is a liquid crystal polymer (liquid crystal polymer). The fiber has a strength of up to two times compared with kevlar.

c. Yarn nets spider (Spider Silk)

Yarn nets spider

Yarn nets spider

Net spider silk protein molecules consist of long bonds. This thread not only has the ability to be able to withstand extreme loads, but also at the same time has a very high elasticity properties, can be drawn up that extends as much as 40%. The elastic properties derived from the grains of fluid contained in the yarn, which judging shaped like a string of pearls or beads.

d. CNT (Carbon Nanotubes)

Discovered in 1991 by Professor Sumio Iijima of Japan. CNT is a composition of carbon C size is very small "nano" (0.000000001) and is shaped like a pipe (tube), whose walls are arranged like a honeycomb. It is estimated that this material is stronger than spider silk.


Principle of Bulletproof Vest

The Principle bulletproof vest is to reduce as much as possible burst of kinetic energy of the bullet, by using layers of fibers to absorb the energy rate and break it down into broad cross-section of the vest, so that energy is not enough anymore to make bullets can penetrate a vest.

In the energy-absorbing rate bullet, vest deforms the pressing towards the inside (shock wave), this added pressure will be forwarded to the user's body. A maximum limit to the emphasis should not be more than 4.4 cm (44 mm). If that limit is exceeded, then the user will experience a deep cut dress (internal organ injuries), which would endanger the safety of life.

The uptake rate of energy that causes the lining vest bullet deformation. The following figure shows that the assumption wearer bulletproof clothing can be spared completely from injury produced by fire is wrong!