SiC/SiC 复合材料涡轮叶片结构设计及静强度评价

A superalloy low-pressure turbine blade was taken as a reference，and the feasibility of SiC/SiC composites for the structural design of this type of turbine blade was studied. The macro design，dovetail design and detail design of the blade were successively conducted. The deformation and stress characteristics of the metal and composite turbine blades were calculated. Tensile tests of the turbine blades prepared according to the above design were carried out，and the deformation of blade body and dovetail was monitored during the tests. The calculation results showed that the elongation of the SiC/SiC-composite blade was lower than that of original metal blades under rated condition. The stress level at the transition between blade root and listrium was relatively high，but lower than the ultimate tensile strength of the SiC/SiC composites. There was a risk of local shear failure at the neck of the dovetail. The results of the experiments indicated that the eventual failure of the blades distinctly exhibited a tensile failure mode，and the coefficient of the margin of strength calculated by the rotate speed at fracture was about 1.3. This structural design method adopted proved feasible，and the SiC/SiC-composite blades successfully passed the static strength tests under the laboratory condition.