Influence of applied in-plane strain on transverse thermal conductivity of 0°/90° and plain weave ceramic matrix composites

• Published in: International journal of solids and structures 2011-03, Vol.48 (5), p.828-842
• Main Authors: Zhang, Daxu, Hayhurst, D.R.
• Format: Article
• Language: English
• Subjects: 0–90 uni-directional and woven composites; Applied sciences; Ceramic matrix composites; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Heat conduction; Heat transfer; Orthotropic material; Physics; Polymer industry, paints, wood; Solid mechanics; Structural and continuum mechanics; Technology of polymers; Thermal conductivity degradation; Tows; Unit cell
• ISSN: 0020-7683; 1879-2146
• DOI: 10.1016/j.ijsolstr.2010.11.017

A computationally economic finite-element-based stress analysis model, developed previously by the authors, has been extended to predict the thermal behaviour of ceramic matrix composites with strain-induced damage. The finite element analysis utilises a solid element to represent a homogenised orthotropic medium of a heterogeneous uni-directional tow. The non-linear multi-axial strain dependent thermal behaviour has been discretised by multi-linear curves, which have been implemented by a user defined subroutine, USDFLD, in the commercial finite element package, ABAQUS. The model has been used to study the performance of two CMC composites: a SiC (Nicalon) fibre-calcium aluminosilicate (CAS) matrix, 0°/90° cross-ply laminate Nicalon-CAS; and, carbon fibre-dual carbon-SiC matrix (C/C-SiC), plain weave laminate DLR-XT. The global through-thickness thermal conductivity degradation with composite uni-axial strain has been predicted. Comparisons have been made between the predictions and experimental data for both materials, and good agreement has been achieved. For the Nicalon-CAS 0°/90° cross-ply the dominant mechanism of thermal conductivity degradation is combined fibre failure and associated wake debonding; and, for the DLR-XT plain weave the same mechanisms act in combination with out-of-plane shear failure.