INDENTABILITY OF CONVENTIONAL AND NEGATIVE POISSONS RATIO FOAMS

The indentation resistance of foams, both of conventional structure an d of a novel re-entrant structure giving rise to negative Poisson's ra tio, was studied using holographic interferometry. In holographic inde ntation tests, re-entrant foams had higher yield strengths sigma(y) an d lower stiffness E than conventional foams of the same original relat ive density. Damage in both kinds of foam occurred primarily directly under the indenter. Calculated energy absorption for dynamic impact is considerably higher for re-entrant foam than conventional foam.