Prediction of thermo-mechanical fatigue life of superalloy components

Important results from the project

The aim of the project is first to develop an efficient method to predict life of commercial aircraft engine subcomponents which are exposed to cyclic thermomechanical loads with hold time effects and secondly to determine material parameters for a selected superalloy. Material parameters for the superalloy Haynes 282 has been determined for rate independent plasticity and the experiments have been successfully modeled. Even cyclic softening could be captured. Methods for rate dependency and life prediction will be studied in the project continuation within NFFP6.

Expected long term effects

The expected result is that GKN will have efficient methods to determine the response and life in commercial aircraft engine subcomponents. The identified methods for rate independent plasticity except for cyclic softening are available at GKN but since the experiments on Haynes 282 have been made on test specimens with another heat treatment than prescribed by GKN, the results have not been used yet.

Approach and implementation

The thought is to use available methods as much as possible and develop them if necessary to capture certain phenomena. A tight cooperation with the syster project is foreseen. The studied phenomena within rate-independent plasticity could be modeled accurately enough with available methods. These methods are however not always available in commercial FE-codes. The tight cooperation with the syster project has been rewarding. Due to problems with the test equipment and test specimens, the material modeling project has come ahead of the test project which is not optimal.