Optimum turbine wheel geometry for passenger car gas turbine has been calculated for two ceramic materials: hot pressed silicon nitride and densified silicon carbide. Two iterative strategies, coupling the mathematical programming techniques with methods of finite elements and finite differences, were used for finding the disk with minimum failure probability. The influences of mean strength, Weibull modulus, and the disk form on the failure probability are presented. The results distinctly show that an improvement in material quality is necessary if the ceramic gas turbine wheel is to become a dependable component.
