Thermal transport property prediction of a CMC laminate from base materials properties and manufacturing porosities

Abstract

This paper reviews two publications of the authors. The first relates to the classification of manufacturing porosity of a ceramic matrix composite material DRL-XT and the second to the quantification of thermal property degradation, due to porosity, at the level of the fibre tow and matrix regions. The paper then shows how these degraded thermal properties can be used in macro unit cell finite element analyses to quantify the effect of manufacturing porosity on bulk composite thermal properties. The dominant porosity type is matrix cracking, which is responsible for a 25% reduction of in-plane bulk thermal conductivity. Key to the success of the approach is an accurate knowledge of thermal properties of the constituent materials. However, in their absence, it is shown how property bounds may be used coupled with: semi-inverse finite element unit cell modelling and experimental values of bulk composite thermal properties.