Evaluation of homogenized thermal conductivities of imperfect carbon-carbon textile composites using the Mori-Tanaka method

TL;DR

This paper presents a three-scale homogenization method using the Mori-Tanaka scheme to estimate the effective thermal conductivities of porous carbon-carbon textile composites, accounting for manufacturing imperfections and voids.

Contribution

It introduces a novel three-scale homogenization approach incorporating pore effects and imperfections for more accurate thermal conductivity predictions.

Findings

Numerical predictions agree well with experimental data.

The method effectively accounts for manufacturing imperfections.

Pore presence significantly influences thermal conductivity estimates.

Abstract

Three-scale homogenization procedure is proposed in this paper to provide estimates of the effective thermal conductivities of porous carbon-carbon textile composites. On each scale - the level of fiber tow (micro-scale), the level of yarns (meso-scale) and the level of laminate (macro-scale) - a two step homogenization procedure based on the Mori-Tanaka averaging scheme is adopted. This involves evaluation of the effective properties first in the absence of pores. In the next step, an ellipsoidal pore is introduced into a new, generally orthotropic, matrix to make provision for the presence of crimp voids and transverse and delamination cracks resulting from the thermal transformation of a polymeric precursor into the carbon matrix. Other sources of imperfections also attributed to the manufacturing processes, including non-uniform texture of the reinforcements, are taken into consideration through the histograms of inclination angles measured along the fiber tow path together with a particular shape of the equivalent ellipsoidal inclusion. The analysis shows that a reasonable agreement of the numerical predictions with experimental measurements can be achieved.