Bullet-proof shields of hard sheet metal backed by resin bonded fibres - to inhibit penetration by soft pointed bullets

摘要

A riot shield is made of a layer of hard ductile material backed by a relatively thick layer of fibrous or laminated material having a moderate delamination energy. Used for shields required to protect both against shrapnel and against bullets from small arms fire. Lighter and more portable than shields involving thick metal or ceramic layers to exlude bullets. The metal layer is sufficient to convert the bullet to a blunt shape which can then be stopped by progressive delamination of the fibrous layer of the shield. The steel should have an elastic yield stress limit of =1000 N/mm2 and a thickness 0.3 x the anticipated bullet calibre. The fibrous layer is made of low modulus glass or organic fibres bonded to each other and to the rear face of the metal layer by e.g. a rubber or polyester resin.