Effect of residual interface stresses on effective specific heats of multiphase thermoelastic nanocomposites

The interfaceenergy theory developed by Huang et al. is further extended to incorporate the effect of the residual interfacestresses on the effective specific heats of multiphase thermoelastic nanocomposites. First, a micromechanics-based method is employed to derive the expressions of the effective specific heats at constant-strain and constant-stress of the composites. Second, in order to take into account the influence of the interfacestresses on the overall properties of the nanocomposites, a thermoelastic interfaceconstitutive relation expressed in terms of the first Piola–Kirchhoff interfacestresses and the Lagrangian description of the generalized Young–Laplace equationsare presented. Finally, by means of the Helmholtz free energyof the “equivalent inclusion” (the inclusion together with its interface), analytical expressions of the size-dependent effective specific heats of the nanocomposites are obtained. The model is illustrated by an example of a “three-phase thermoelastic composite” showing that the overall properties of the nanocomposites are influenced by the “residual interfacestresses,” which was sometimes ignored in the literature.