A Finite-element analysis of the thermal diffudivity/conductivity of SiC/SiC composites

Yamada, Reiji; Igawa, Naoki   ; Taguchi, Tomitsugu

A Finite-element method(FEM) was applied for a computer simulation of a laser flash method for measuring thermal diffusivity of SiC/SiC composites. To understand the effect of individual fiber and matrix thermal conductivities as well as fiber volume on the overall composite's thermal diffusivity, the cases of high and low values for the fiber and matrix thermal conductivities were calculated as a function of fiber volume fraction at specimen temperatures of 200 and 900. The results of calculations showed that if low thermal conductive SiC fibers were used, the increase of fiber volume worsened the composite thermal diffusivity with highly conductive matrix, whereas when using highly conductive SiC fiber, the effect of increasing fiber volume was positive for increasing the composite diffusivity with low matrix thermal conductivity. The specimen temperatures altered the values of the composite thermal diffusivity but the qualitative tendencies above mentioned were maintained.