Why kevlar works

Kevlar is a synthetic fiber Invented by Stephanie Kwolek in whilst working for the Chemical giant Dupont. She knew that atoms are the smallest part of a piece of matter or chemical element and that they have strong bonds.

Organic ones are things like wool and silk and protein but human-made polymers are things like plastic. Whilst searching for a new plastic to make lighter, stronger car tires, Stephanie Kwolek discovered the molecule Poly Paraphenylene Terephthalmide. It is a polymer with an exciting secret…the molecules can be laid out in chains, side-by-side to create a hugely strong mesh that can also be spun into fabric! And, added bonus, it can resist high heat and flames of up to around degrees!

You have a new low-weight-high-impact body armor! Well Kevlar is a bit like thousands of stiff fishing nets all laid on top of each other. At its heart, a piece of bullet-proof material is just a very strong net. To see how this works, think of a soccer goal. The back of the goal consists of a net formed by many long lengths of tether, interlaced with each other and fastened to the goal frame. When you kick the soccer ball into the goal, the ball has a certain amount of energy, in the form of forward inertia.

When the ball hits the net, it pushes back on the tether lines at that particular point. Each tether extends from one side of the frame to the other, dispersing the energy from the point of impact over a wide area. The energy is further dispersed because the tethers are interlaced. When the ball pushes on a horizontal length of tether, that tether pulls on every interlaced vertical tether.

These tethers in turn pull on all the connected horizontal tethers. In this way, the whole net works to absorb the ball's inertial energy, no matter where the ball hits. If you were to put a piece of bulletproof material under a powerful microscope , you would see a similar structure.

Long strands of fiber are interlaced to form a dense net. A bullet is traveling much faster than a soccer ball, of course, so the net needs to be made from stronger material.

KEVLAR is lightweight, like a traditional clothing fiber, but it is five times stronger than a piece of steel of the same weight. When interwoven into a dense net, this material can absorb a great amount of energy. In addition to stopping the bullet from reaching your body, a piece of body armor also has to protect against blunt trauma caused by the force of the bullet.

To make the fabrics used in bulletproof panels that Kevlar yarn is woven into a fabric sheet. Several sheets of the woven Kevlar fabric are then stitched together to make the bulletproof panels inside a ballistic vest.

The proper amount of the fabric layers is determined by testing against various types of handgun and rifle ammunition and matched against known threat protection standards. Each threat protection level is matched against a particular type of threat like handguns, rifles and even armor piercing ammunition.

At the highest threat protection levels the Kevlar soft armor panels might be supplemented by ceramic hard armor plates. A few threads may break but not enough to create a path for the bullet. The energy of the bullet is then dissipated outward instead of punching through the fabric. Save my name, email, and website in this browser for the next time I comment. How does Kevlar work? How is bulletproof clothing made?