A Design Feasibility Study of a Turbine Blade Disc Interface (Dovetail) Made By Four-Directional Braided Ceramic Matrix Composite (Sic/Sic)

The blade and disc's interface region (dovetail) is an integral part that plays an essential role in advanced flight machines. In this region, the major source of stress arising is the rotation of an engine shaft. Concerning this, geometry, material selection, and stress calculation need to perform at the predesign phase. This paper proposes four-directional braided ceramic matrix composites (CMCs) for the dovetail region because of its high transverse and shear strength, with less weight and thermal resistance. Due to the heterogeneous characteristics of proposed four-directional CMCs, homogenized mechanical properties are calculated for dovetail under non-isotropic conditions using multi-scale modeling and mechanics of structure genome method (MSG) for homogenization. After optimizing the dimensions for shape and minimizing the mass in the design study, the estimated homogenized mechanical properties are used to conduct a three-dimensional non-linear finite element (FE) analysis of the disc-dovetail assembly to check the feasibility of braided CMC’s dovetail over conventional dovetail. A comparative study between conventional and proposed dovetail material is made for the first time using the FE analysis results. Four-directional braided CMC (SiC/SiC) fits the blade disc interface region from a strength point of view because it shows less deformation, stress, and high stability than conventional Ti-alloy.