Elastomer–steel laminate armor

Elastomeric coatings have been found to substantially increase the ballistic limit of underlying steel substrates, with an important mechanism being the impact-induced transition of the rubber to the glassy state. A composite array of elastomer–steel panels has been found to further increase the penetration resistance; moreover, the elastomer coating itself can be a laminate structure of soft and hard materials. The requirements for the laminate to function well are that the underlying substrate retains sufficient bending stiffness for the impact to induce the transition of the polymer, which in combination with break up and dissipation of the pressure wave due to impedance mismatching, leads to large increases in ballistic penetration resistance.