Projectile penetration into rock/elastomer composites
Composite materials cast from polyurethane resin, rack aggregates and sand have been examined to determine their resistance to penetration by 7.62mm ball and armour piercing high velocity projectiles. The effects of using different " polymer and rock types were investigated, and the resultant composite mixes were optimised in'terms of cost effectiveness to obtain a protective material which may be used to clad buildings. Optimisation was carried out using response surface theory, initially using a linear response surface; but subsequently a quadratic one. Variables considered in the mix optimisation were % polymer by weight, % rock aggregate by weight, rock aggregate particle size, and polymer hardness. Penetration tests were carried out on the optimised composites to determine the thickness required for a given confidence level of bullet containment, and to assess the effect of composite temperature on impact behaviour. The static uniaxial compressive, bending and creep characteristics of the best composite were determined to identify any limitations in its use as cladding units.