An exploration of structure design in 3D braided ceramic matrix composites turbine blade dovetail attachment

For braided composites, the direction of yarns and its braided density could vary with the parts’ shape, the braided method of the composites could be designed according to the structure actual shape. In order to research the local mechanical properties variation of braided composites causing by geometric change of the structure, explore the method to design 3D braided ceramic matrix composites (CMCs) parts with complex geometrical shape. Choosing the 3D braided CMCs turbine blade dovetail attachment as the background, selected its two-dimensional section as the research object. Firstly assumed the CMCs’ properties are transversely isotropic along the section plane, analyzed the structural stress distribution. Considering the requirement of CMCs forming process and its strength data, the preliminary structure design could be established. Then, in view of the local mechanical properties variation of CMCs happening in the transition of structures shape, several microcosmic cell model was established to obtain the elastic properties respectively in different areas using the finite element method. Substituting these properties into the corresponding area of the section, the result of the stress level of the structure section would be closer to the practical situation. The structure design method and the obtained key structure parameters can be used as a reference in the future work.