Grüneisen Tensor of an Anisotropic Composite

Abstract

A phenomenological model of an anisotropic composite, quartz phe nolic, is presented. The model assumes that the quartz phenolic macro scopically has the same symmetry properties as a hexagonal single crystal. The formalism relating the Gruneisen tensor to elastic constants, coefficients of thermal expansion, and specific heat was applied to the composite, and the Gruneisen parameters were evaluated from measured values of these quantities. Further, direct measurements of the Gruneisen parameters were accomplished by means of an electron beam induced stress wave technique, and the resulting values were compared with those computed from the elastic and thermal data. Electron beam data produced values Γ_x = 0.23 ± 0.03 and r = 0.28 ± 0.03, while the values of the Gruneisen parameters computed from the elastic and thermal data were somewhat higher than the electron beam results. The analysis demonstrated the utility of symmetry properties for the characterization of heterogeneous materials.