bulletproof kevlar

[dianfirmansy]

what exactly the property that make a kevlar sheet unpenetrable by bullet? Is it the tensile strength, breaking strength, stiffness, or others? Thanks.

[Hamish]

Its more than just the Kevlar. It need to be prepared as a fabric and woven correctly. The strength stops immediate penitration and the energy is dissipated over a large area (the weaving bit). Its more complex than a simple material property.

[heathfield]

Read about the discovery of Kevlar here

[Skids]

It takes at least fifty layers of Kevlar matting in a composite structure to make it bulletproof. The problem with Kevlar is its ability to absorb water. It absorbes water quicker than Carbon composite. When a composite absorbs water it starts to delaminate and looses its desirable properties.