Frequency dependent thermal expansion in binary viscoelasticcompositesperBerryman, James G.USDOE Director. Office of Science. Basic Energy SciencesorgUnited States. Department of Energy. Office of Basic Energy Sciences."Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States)"Berkeley, CaliforniaLawrence Berkeley National Laboratory2007-12-01engThe effective thermal expansion coefficient beta* of abinary viscoelastic composite is shown to be frequency dependent even ifthe thermal expansion coefficients beta A and beta B of both constituentsare themselves frequency independent. Exact calculations for binaryviscoelastic systems show that beta* is related to constituent valuesbeta A, beta B, volume fractions, and bulk moduli KA, KB, as well as tothe overall bulk modulus K* of the composite system. Then, beta* isdetermined for isotropic systems by first bounding (or measuring) K* andtherefore beta*. For anisotropic systems with hexagonal symmetry, theprincipal values of the thermal expansion beta*perp and beta*para can bedetermined exactly when the constituents form a layered system. In allthe examples studied, it is shown explicitly that the eigenvectors of thethermoviscoelastic system possess non-negative dissipation -- despite thecomplicated analytical behavior of the frequency dependent thermalexpansivities themselves. Methods presented have a variety ofapplications from fluid-fluid mixtures to fluid-solid suspensions, andfrom fluid-saturated porous media to viscoelastic solid-solidcomposites.EigenvectorsSymmetryThermal Expansion Composites Thermal Expansion Viscoelasticity54MixturesComposites Thermal Expansion Viscoelasticity