Aircraft engine systems and methods for operating same

1. A method for determining a residual life expectancy of a rotor of a gas turbine, the method comprising:

operating the gas turbine and acquiring operating conditions of the gas turbine;

inspecting the rotor of the gas turbine and obtaining a gas turbine rotor inspection result;

updating, based on the operating conditions of the gas turbine and the gas turbine rotor inspection result, a database for a fleet of a class of gas turbines having a set of common characteristics corresponding to the gas turbine; and

calculating the residual life expectancy of the rotor of the gas turbine and an associated risk to life extension,

wherein the calculating step further comprising:

measuring independent variables of the gas turbine; and

using physical models of the gas turbine to calculate a plurality of dependent variables of the gas turbine based on the independent variables.

2. The method of claim 1 , wherein inspecting the rotor of the gas turbine comprises determining if a crack in the rotor is present, a usage indication in the rotor is present, or no event in the rotor is present.

3. The method of claim 2 , wherein if an unexpected crack in the rotor is present, modifying a model of the gas turbine.

4. The method of claim 2 , wherein if the usage indication in the rotor or an expected crack is present, calculating the residual life expectancy of the rotor for the usage indication or the expected crack.

5. The method of claim 2 , wherein the usage indication is a mark, a scratch, or a print in the rotor, or a combination thereof.

6. The method of claim 1 , further comprising:

providing the independent variables as input to transfer functions for calculating life variables, wherein a life variable is a cycles-to-LCF (low cycle fatigue) crack initiation parameter.

7. The method of claim 6 , further comprising:

executing MonteCarlo simulations based on the independent variables, and distributions of the independent variables.

8. The method of claim 6 , further comprising:

executing Monte Carlo simulations based on the independent variables, distributions of the independent variables, and transfer functions to determine a fleet probabilistic life.

9. The method of claim 8 , further comprising:

calculating the residual life expectancy of the rotor of the gas turbine based on the independent variables, the transfer functions, the Monte Carlo simulations, and destructive lab tests.

10. The method of claim 1 , wherein the independent variables of the gas turbine is an ambient temperature, a rotor speed, a firing temperature, or geometrical clearances, or a combination thereof; and the dependent variables is cycles-to-LCF (low cycle fatigue) crack initiation, hours to creep crack initiation, or hours or cycles for a crack to propagate to failure, or a combination thereof.

11. The system of claim 10 , wherein if an unexpected crack in the rotor is present, the system is configured to modify a model of the gas turbine.

12. The system of claim 10 , wherein if the usage indication in the rotor or an expected crack is present, the system configured to calculate the residual life expectancy of the rotor for the usage indication or the expected crack.

13. The system of claim 10 , wherein the usage indication is a mark, a scratch, or a print in the rotor, or a combination thereof.

14. A system configured to determine a residual life expectancy of the gas turbine component, the system further configured to:

operate the gas turbine and acquiring operating conditions of the gas turbine;

inspect the rotor of the gas turbine and obtaining a gas turbine rotor inspection result;

update, based on the operating conditions of the gas turbine and the gas turbine rotor inspection result, a database for a fleet of a class of gas turbines having a set of common characteristics corresponding to the gas turbine, and

calculate the residual life expectancy of the rotor of the gas turbine,

wherein the system configured to calculate the residual life expectancy further comprising the system configured to:

measure independent variables of the gas turbine; and

use physical models of the gas turbine to calculate a plurality of dependent variables of the gas turbine based on independent variables.

15. The method of claim 1 , further comprising conducting destructive tests on the rotor of the gas turbine.

16. The system of claim 14 , wherein the independent variables of the gas turbine is an ambient temperature, a rotor speed, a firing temperature, or geometrical clearances, or a combination thereof; and the dependent variables of the gas turbine is cycles-to-LCF (low cycle fatigue) crack initiation, hours to creep crack initiation, or hours or cycles for a crack to propagate to failure, or a combination thereof.

17. The system of claim 14 , wherein the system configured to inspect the rotor of the gas turbine further comprising the system configured to determine if a crack in the rotor is present, a usage indication in the rotor is present, or no event in the rotor is present.

18. The system of claim 14 , wherein the system configured to calculate the residual life expectancy further comprising the system configured to provide the independent variables as input to transfer functions for calculating life variables, wherein a life variable is a cycles-to-LCF (low cycle fatigue) crack initiation parameter.