Design methodology to investigate contact fatigue damage in turbine engine hardware

One of the most significant maintenance drivers in current turbine engines is contact fatigue damage where turbine blades are inserted into the disk. This is commonly referred to as the dovetail slot. The stress state at the dovetail slot is difficult to determine with standard finite element analysis because of the nonlinear nature of the contact problem. Because of this, a design methodology based on singular integral equation analysis has been developed. This design methodology is used for the first time to compare the contact stress behavior of similar components from two different turbine engines. The use of singular integral equation methods to analyze these components is supported by a similar analysis on a dovetail experimental fixture. Stress predictions by the singular integral equation method compare well to finite element methods for static stress conditions in a dovetail slot. Additionally, the results from the component analysis indicate that there is a correlation between stress state and damage seen during maintenance. However, details concerning the correlation still need to be resolved.