CONDITION BASED LIFING OF GAS TURBINE ENGINE COMPONENTS

• US 20150105966A1
• Filed: 10/11/2013
• Published: 04/16/2015
• Est. Priority Date: 10/11/2013
• Status: Active Grant

• Current Assignee: Solar Turbines Incorporated (Caterpillar Incorporated)
• Original Assignee: Solar Turbines Incorporated (Caterpillar Incorporated)
• Inventors: Green, Richard James, Novaresi, Mark Alfred, Bollapragada, Sudhakar
• Granted Patent: US 9,200,984 B2
• Time in Patent Office: Days
• US Class Current: 701/29.4
• CPC Class Codes: G01M 15/14 Testing gas-turbine engines or jet-propulsion engines
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06
• CPC Class Codes: G07C 5/006 Indicating maintenance

Abstract

A system and methods for the condition based lifing of a gas turbine engine component is disclosed. The system and methods determine the stress and caused by fatigue and creep for each load cycle of the gas turbine engine, and use a ductility exhaustion method to combine the fatigue and creep strain rates determined from the fatigue and creep stresses to determine the remaining useful of the gas turbine engine component.

Claims

1. A method for determining a remaining useful life for a component in a gas turbine engine based on operating conditions for each load cycle of the gas turbine engine, each load cycle including one or more ramp periods and one or more dwell periods, the method comprising:

recording field data of the gas turbine engine for each load cycle the component is in the gas turbine engine;

determining a life consumed of the component for each load cycle the component is in the gas turbine engine including

determining a ramp period life consumed for each ramp period using a ductility exhaustion curve for a material of the component and a ramp period stress of the load cycle determined using the field data,

determining a dwell period life consumed for each dwell period using the ductility exhaustion curve and a dwell period stress of the load cycle determined using the field data, and

combining the ramp period life consumed from each ramp period and the dwell period life consumed from each dwell period to determine a life consumed for the load cycle;

determining a total life consumed by summing the life consumed for each load cycle; and

determining a remaining useful life of the component by subtracting the total life consumed from a declared service life.

2. The method of claim 1, wherein the remaining useful life is a number of cycles and hours of life remaining operating at a rated condition.

3. The method of claim 2, wherein the declared service life is a total number of cycles and hours to exhaust the ductility at a rated condition.

4. The method of claim 1, wherein the remaining useful life for the component is determined after each load cycle of the gas turbine engine.

5. The method of claim 1, wherein the material is a superalloy.

6. The method of claim 1, wherein the material is an anisotropic material.

7. A method of service, wherein when to replace the component is based on the component reaching a predetermined threshold of the remaining useful life determined by the method of claim 1.

8. A method of service, wherein when to perform service on the gas turbine engine is determined by projecting when the component will reach a predetermined threshold of the remaining useful life determined by the method of claim 1.

9. A method for determining a remaining useful life for a component in a gas turbine engine based on operating conditions for each load cycle of the gas turbine engine, the method comprising:

recording operational data of the gas turbine engine including data for each load cycle of the gas turbine engine that the component is in the gas turbine engine, each load cycle including one or more ramp periods and one or more dwell periods;

determining a ramp period stress for each ramp period of each load cycle using the operational data;

determining a ramp period strain for each ramp period from the ramp period stress using a stress-strain curve for a material of the component;

determining a ramp period strain rate for each ramp period from the ramp period strain, determining a ramp period damage for each ramp period from the ramp period strain rate by using a ductility exhaustion curve for the material;

determining a dwell period stress for each dwell period of each load cycle using the operational data;

determining a dwell period strain for each dwell period from the dwell period stress and temperature using a creep strain curve;

determining a dwell period strain rate for each dwell period from the dwell period strain,

determining a dwell period damage for each dwell period from the dwell period strain rate by using the ductility exhaustion curve;

combining the ramp period damage for each ramp period and the dwell period damage for each dwell period to get the damage accumulated on the component during each load cycle;

determining a total damage accumulated by summing the damage accumulated for each load cycle; and

determining a remaining useful life of the component by subtracting the total damage accumulated from a total available ductility.

10. The method of claim 9, wherein the remaining useful life is a percentage of the total available ductility relative to the total damage accumulated.

11. The method of claim 10, wherein the total available ductility is determined by using creep and tensile test data.

12. The method of claim 9, wherein the remaining useful life is determined for the component and simultaneously for other gas turbine engine components.

13. A method of service, wherein when to replace the component is based on the component reaching a predetermined threshold of the remaining useful life determined by the method of claim 9.

14. A method of service, wherein when to perform service on the gas turbine engine is determined by projecting when the component will reach a predetermined threshold of the remaining useful life determined by the method of claim 9.

15. A condition based lifing system for a component of a gas turbine engine, the condition based lifing system comprising:

a processor;

a material data store including a stress-strain curve and a ductility exhaustion curve for a material of the component;

a gas turbine engine data store including operating conditions of one or more load cycles of the gas turbine engine, each load cycle including a ramp period and a dwell period;

a fatigue module configured to determine a plastic stress of the component for each ramp period, and determine a plastic strain rate from the plastic stress;

a creep module configured to determine a viscoplastic stress of the component for each dwell period and determine a viscoplastic strain rate from the viscoplastic stress; and

a ductility exhaustion module configured to determine a remaining useful life of the component by determining an exhausted ductility of the component using the plastic strain rate, the viscoplastic strain rate, and the ductility exhaustion curve, and subtracting the exhausted ductility from an available ductility.

16. The condition based lifing system of claim 15, wherein the material is a superalloy.

17. The condition based lifing system of claim 15, wherein the ductility exhaustion module determines the remaining useful life for multiple components of the gas turbine engine simultaneously.

18. The condition based lifing system of claim 15, further comprising electronic instruments configured to provide the operating conditions of the one or more load cycles of the gas turbine engine to the gas turbine engine data store.

19. The condition based lifing system of claim 15, wherein the lifing system is located remotely to the gas turbine engine and is used to remotely monitor and manage the gas turbine engine from a central location.

20. A service system, wherein when to perform service on the gas turbine engine is determined by projecting when the component will reach a predetermined threshold of the remaining useful life determined by the condition based lifing system of claim 15.