Developments in Ceramic Materials Research

Modeling of Thermal Transport in Ceramics Matrix Composites 201
Figure 30. Edge slivers meshed with refined local seed adjustment.
4.1. Thermal Analysis
The boundary conditions set have been shown in Figure 31 for 1D Steady State heat flow
in x-direction. A temperature gradient is applied across the section of the Unit Cell to allow
heat flow in the direction for which the average thermal transport property is required. For the
determination of kx, as in this case, a temperature gradient ‘ Δ T Δx
’ is applied in the xdirection
and the average heat flux, qx, is calculated for use in Eq. (12). All intermediate outer
surfaces are assumed perfectly insulated ( δ T δ n = 0 ). The adiabatic condition is set by
default on all surfaces by ABAQUS/CAE when the temperatures on two faces are set in the
initial step. The temperature is given a value of To = 100 degrees on front face, where as for
the rear face, no change is made and it remains at the default zero temperature state, creating
a difference of Δ T = 100 across.
In spite of the minimal availability of precise constituent material data, a selection has
been made from within reasonable bounds for material thermal property values. This exercise
has also established a preliminary benchmark for assessing various computational aspects in
the analyses. For true comparisons, first the basic execution of a single RVE Unit Cell
analysis had to be perfected. More importantly, the choice of this RVE geometry had also
been geared towards the fact that the complete CMC laminate could be modeled by simple
replication of its Unit Cell. This has been achieved by sequentially joining multiple Unit Cells