Auxetic foams - Materials exhibiting negative Poisson's ratios and other superior properties

摘要

As a standard piece of foam is stretched, one expects it to get thinner, a property which is characteristic of most conventional materials. The extent of thinning that a material undergoes when it is subjected to a uniaxial strain is quantified by the Poisson's ratio. In particular, if a material is subjected to a strain e. in the Ox. direction with the result that it changes its dimension in an orthogonal Ox. direction, then one may define the Poisson's ratio in the Ox- Ox.