FEM study and optimisation of a CMC outer liner

The possible employment of ceramic matrix composites (CMCs) in place of metals in the hot parts of the turbo machines is studied. The use of this class of materials should allow a relevant increase in the temperature of the gas with an increase in the overall efficiency. The CMC under study is a 12 layers laminate composed of alumina fibres embedded in a mullite matrix mounted with a crossply architecture. Thermal and stress analyses of a FE model of an outer liner is performed, and results are presented. These results are not completely satisfactory, and an optimisation process is applied to the component to identify that best material configuration, which results in six layers with an angleply architecture. An evident improvement is obtained, as the resulting stress level is significantly reduced.