THERMOMECHANICAL DESIGN AND ANALYSIS OF CERAMIC COMPOSITE EXHAUST DIFFUSER UNIT

The exhaust diffuser unit of a modern ail breathing engine has been ch osen for a design study using ceramic composites as part of a wider re search programme to introduce new materials into aeroengines. Although the unit is relatively, lightly stressed, it is subject to a severe t hermal environment, and poses a significant lest of the behaviour of n ew materials. Material selection has been based on deformation maps, u sing merit parameters for strength and toughness under thermal shock. Heat transfer analysis of the conceptual design has established the th ermal transients, and allowed the estimation of thermally induced stre sses. The stress levels are sufficient to induce microcracking in cera mic composites, and have required the development of a simple damage m echanics model. (C) 1995 The Institute of Materials.