Deformations of Foamed Elastomers

Geometrical shapes of interstices of two types of closest packing of uniform spheres, 1) hexagonal closest packing, 2) face centered cubic closest packing are studied, and the structures of interstices of these two types of packing are used to represent those of the actual foamed elastomers. Equivalent elastic constants for these two structures are calculated in terms of the slenderness of a thread (which is a function of voids content) l'/A where l is the length of a thread and A its cross-sectional area, and of the elastic constants of the interstices. The calculated value of Poisson's ratio of a model containing 67 percent of the interstices of hexagonal closest packing and 33 percent those of face centered cubic packing corre lates fairly well with existing experimental data.