THE STATIC AND IMPACT BEHAVIOR OF POLYMER COMPOSITE SANDWICH BEAMS

The static and dropped weight impact performance of polymer composite sandwich beams has been investigated in a three-point bend configuration. The skin materials examined included woven fabrics of glass, carbon and aramid fibre, as well as glass chopped strand mat. The core materials were Coremat(TM) (resin-impregnated non-woven polyester) and Aeroweb(TM) aluminium honeycomb. Polyester and epoxy resin matrices were used. The static failure modes of beams with various Gore and skin combinations are discussed. The dominant failure modes for both glass/Coremat and glass/Aerolam(TM) beams involved upper skin failure in the vicinity of the penetrator. The dropped weight impact performance of the latter two types of beam, at impact speeds of up to 7.5 m s(-1), was investigated. The Coremat-cored beams showed marked rate dependence effects, with failure energies reducing to a minimum at a given drop height and then increasing again with increasing drop height. The honeycomb-cored beams showed only slight rate dependence. The dynamics of the beam tests are discussed in terms of mass spring models and times to failure in the upper skins highlighted.