Method and system for real-time prognosis analysis and usage based residual life assessment of turbine engine components and display

• US 20110137575A1
• Filed: 10/19/2007
• Published: 06/09/2011
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Ashok Koul
• Original Assignee: Ashok Koul
• Inventors: Koul, Ashok
• Granted Patent: US 8,116,990 B2
• Time in Patent Office: Days
• US Class Current: 702/34
• CPC Class Codes: G05B 23/0245 based on a qualitative model, e.g. rule based; if-then decisions
• 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

Abstract

A method and system for performing continuous (real-time) physics based prognostics analysis as a function of actual engine usage and changing operating environment. A rule-based mission profile analysis is conducted to determine the mission variability which yields variability in the type of thermal-mechanical loads that an engine is subjected to during use. This is followed by combustor modeling to predict combustion liner temperatures and combustion nozzle plane temperature distributions as a function of engine usage which is followed by off-design engine modeling to determine the pitch-line temperatures in hot gas path components and thermodynamic modeling to compute the component temperature profiles of the components for different stages of the turbine. This is automatically followed by finite element(FE) based non-linear stress-strain analysis using an real-time FE solver and physics based damage accumulation, life consumption and residual life prediction analyses using microstructural modeling based damage and fracture analysis techniques.

Claims

1. A physics based prognostics system for real-time prediction of remaining life prior to crack or flaw nucleation and prediction of residual life of engine components in the presence of a flaw or distortion, the system comprising:

a graphical user input interface for inputting in-service machine operating data collected from sensors and signal processing modules installed in a machine under investigation, finite element model and quantitative microstructural and internal state variable material parameters of a component of the machine, temperature dependent physical and mechanical properties of the component material including creep, low cycle fatigue, thermal mechanical fatigue, high cycle fatigue, creep crack growth rate, fatigue crack growth rate oxidation, hot corrosion, corrosion fatigue, into a prognostics software database,

a prognostics processor that contains materials engineering based damage rules and material microstructure and internal state variables based damage accumulation and fracture models for receiving the data from the database and for processing the data to provide output information indicative of remaining life prior to flaw or crack nucleation and residual life of engine components in the presence of a flaw or distortion, and

an output interface for displaying the output information from the processor, indicative of the remaining life prior to flaw or crack nucleation, life consumed and residual life in the presence of a flaw in engine components.

2. The system according to claim 1, wherein the prognostics processor comprises a material engineering rule-based mission profile analyzer module, a combustor modeling module, an off-design engine analysis module, a thermodynamic modeling module, a non linear finite element analysis module, and a material microstructure and internal state variable based deformation and fracture analysis module.

3. According to claim 2, the output interface comprises distortion and probabilistic flaw or crack nucleation data, crack propagation data, surface condition data and remaining life data prior to flaw or crack nucleation, overhaul and inspection intervals data in the presence of flaws.

4. A method for real-time assessment and prediction of remaining life prior to flaw nucleation and residual life in the presence of flaw or distortion of machine components, the method comprising the steps of:

a) continuously monitoring variability of engine operating parameters and engine operating environment,

b) performing the usage and operating environment based flaw or crack nucleation, crack propagation, distortion, corrosion or erosion analysis for life consumption, remaining life prior to crack nucleation and residual life prediction in the presence of flaws of multiple structural components of a turbine engine,

c) predicting the development of the intrinsic as well as extrinsic state of damage in these structural components before the development of any discernable flaws, faults or damage in these components that may be manufactured out of metallic, ceramic or a combination of both types of materials using standard data acquired from engine monitoring interfaces.

5. The method according to claim 4, wherein the step a) comprises the substeps of

i) collecting and analyzing the data points acquired by each monitoring interface,

ii) performing materials engineering rule based mission profile analysis for assessing the types of thermal-mechanical loads and materials deformation and fracture accumulation modes and mechanisms such as creep, fatigue, combined creep-fatigue environment interactions including variability in loads affecting damage accumulation rates the monitored components are subjected to during service.

6. The method according to claim 4, wherein the step b) comprises the substeps of

i) performing combustor modeling to predict the variability in combustion liner temperatures and combustion nozzle plane temperature distributions as a function of turbine engine usage,

ii) performing off-design engine modeling to determine the variability in pitch-line temperatures in hot gas path components and thermodynamic modeling to compute the variability in component temperature profiles of gas path as well as other rotating components for different stages of the engine as a function of actual turbine engine usage;

iii) performing finite element (FE) based non-linear thermal-mechanical stress-strain analysis as a function of the variability in real time thermal-mechanical loads using an real-time FE solver and performing damage accumulation analysis using materials microstructure and internal state variable based damage and fracture models taking into account the quantitative variability in microstructural parameters in a given row of gas path components or other rotating components in a fleet of engines, and

iv) continuously providing an update of thermal-mechanical loads and quantifying the thermal-mechanical loads.

7. The method according to claim 4, wherein the step c) comprises the substeps of:

i) updating and quantifying the damage accumulation rates using the physics of deformation and fracture processes operative in different components that allows accurate identification of fracture critical locations, estimation of remaining life prior to flaw or crack nucleation, life consumption and residual life of each component being monitored and fluctuations in specific component life parameters over time, and

ii) continuously displaying the variability of fracture critical locations and remaining life prior to flaw or crack nucleation and residual life in the presence of flaws or distortion for each component monitored.

8. The method according to claim 5, wherein the substep ii) comprises continuously computing variability of centrifugal loads and steady state homologous temperatures as well as cyclic homologous temperatures to establish the types of thermal-mechanical loads seen by the components using variability analysis, for each of the components monitored in real-time.

9. The method according to claim 8, further comprising removing artefacts using a modified rain-flow analysis technique in combination with homologous temperature plots to identify undesirable data points and to discern exact microstructure and internal state variable based damage and fracture modes and mechanisms that are operative as a function of turbine engine usage in real time.

10. The method according to claim 6, wherein the substep i) comprises performing physics based combustor modeling for continuously obtaining the variability of combustor liner temperature and combustor nozzle plane temperature profiles as a function of turbine engine usage in real-time using a combustion solver or semi-empirical modeling techniques.

11. The method according to claim 6, wherein the substep ii) comprises continuously computing the variability of centrifugal loads and steady state homologous temperatures as well as cyclic homologous temperatures to establish the types of thermal-mechanical loads seen by the components using variability analysis, for each of the components monitored in real-time.

12. The method according to claim 11, further comprising physics based gas path modeling for continuously obtaining variability of pitch-line temperatures of different turbine engine gas path stages as a function of engine off-design usage conditions in real-time.

13. The method according to claim 11, further comprising physics based thermodynamic modeling including potential flow technique for continuously obtaining variability of two dimensional temperature profiles for different turbine engine gas path stages as a function of turbine engine usage conditions in real-time.

14. The method according to claim 11, further comprising a physics based heat transfer modeling for continuously obtaining variability of component temperature profiles for different turbine engine gas path stages including blades and vanes as a function of turbine engine usage conditions in real-time.

15. The method according to claim 11, further comprising a physics based heat transfer modeling for continuously obtaining variability of temperature profiles for different turbine engine stages for non-gas path components including discs, cooling plates and spacers as a function of turbine engine usage conditions in real-time.

16. The method according to claim 6, wherein the substep iii) comprises performing a non-linear finite element modeling for continuously obtaining variability of stress, strain and temperature profiles for different turbine engine components being monitored as a function of turbine engine usage conditions in real-time.

17. The method according to claim 7, wherein the substep i) comprises performing materials microstructure and internal state variable based damage and fracture modeling for continuously providing variability of distortion driven fracture critical locations, remaining life prior to flaw or crack nucleation, life consumption, residual life and inspection intervals in the presence of flaws for different turbine engine components being monitored as a function of turbine engine usage conditions in real-time.

18. The method according to claim 17, wherein substep i) further comprises performing physics based erosion, corrosion and hot corrosion damage modeling for continuously providing variability of surface degradation driven fracture critical locations, remaining life prior to flaw or crack nucleation, life consumption, residual life and inspection intervals in the presence of flaws for different turbine engine components being monitored as a function of turbine engine usage conditions in real-time.

19. The method according to claim 17, wherein substep i) further comprises performing material microstructure and internal state variable based high temperature creep, cold creep, low cycle fatigue, high cycle fatigue, corrosion fatigue, stress corrosion, thermal fatigue, thermal-mechanical fatigue, creep-fatigue environment interactions damage and fracture modeling for continuously computing variability of flaw or crack nucleation based fracture critical locations, remaining life prior to flaw or crack nucleation, and life consumption for different turbine engine components being monitored as a function of turbine engine usage conditions in real-time.

20. The method according to claim 17, wherein substep i) further comprises performing materials microstructure and internal state variable based creep, fatigue and combined creep-fatigue environment interaction fracture modeling for continuously computing variability of crack propagation based fracture critical locations, life consumption, residual life and safe inspection intervals in the presence of flaws for different turbine engine components being monitored as a function of turbine engine usage conditions in real-time.