BOUNDS AND EXTREMAL ELASTIC-MODULI OF ISOTROPIC QUASI-SYMMETRICAL MULTICOMPONENT MATERIALS

The bounds on the elastic moduli of isotropic multicomponent materials with certain geometric symmetry among the phases are examined. The bo unds of Phan-Thien and Milton and those of Pham for the subclass of sp herical cell materials are identical, while Phan-Thien and Milton's bo unds for the subclass of platelet cell materials, which coincide with Pham's bounds in the case of two-component materials, are tighter in t he general multicomponent case. Geometric models are constructed, whic h verify the optimality of Phan-Thien and Milton's bounds on the bulk modulus of multicomponent platelet cell materials. Subsequently, the r espective bounds for the whole class of isotropic quasisymmetric compo sites are optimal over a range of parameters. (C) 1998 Elsevier Scienc e Ltd. All rights reserved.