Turbine Fatigue Reliability and Life Assessment Using Ultrasonic Inspection: Data Acquisition, Interpretation, and Probabilistic Modeling
A general method and procedure of fatigue reliability and life assessment of steam turbines using ultrasonic inspections is presented in this chapter. The basic structure of an automated ultrasonic inspection system using in turbine surface engineering is briefly introduced. Using the inspection information, a probabilistic model is developed to quantify uncertainties from flaw sizing and model parameters. The uncertainty from flaw sizing is described using a probability of detection model which is based on a classical log-linear model coupling the actual flaw size with the ultrasonic inspection reported size. The uncertainty from model parameters is characterized using Bayesian parameter estimation from fatigue testing data. A steam turbine rotor example with realistic ultrasonic inspection data is presented to demonstrate the overall method. Calculations and interpretations of assessment results based on risk recommendations for industrial applications are also discussed.
KeywordsCombustion Fatigue Covariance Steam Convolution
- Abbasi, W., & Metala, M. (2008). Recent advances in NDE technologies for turbines and generators. In 17th World Conference on Nondestructive Testing.Google Scholar
- Berens, A. P. (1989). NDE reliability data analysis. In: ASM Handbook (vol. 17, 9th edn., pp. 689–701). ASM International.Google Scholar
- Georgiou, G. (2006). Probability of Detection (POD) curves: derivation, applications and limitations. Technical Report 454, Jacobi Consulting Limited, London, UK.Google Scholar
- Guan, X., Zhang, J., Kadau, K., & Zhou, S. K. (2013). Probabilistic fatigue life prediction using ultrasonic inspection data considering equivalent initial flaw size uncertainty. In D. O. Thompson, & D. E. Chimenti (Eds.), AIP Conference Proceedings (vol. 1511, pp. 620–627). AIP.Google Scholar
- Rubinstein, R., & Kroese, D. (2007). Simulation and the Monte Carlo method (vol. 707). Wiley-interscience.Google Scholar
- Schwant, R., & Timo, D. (1985). Life assessment of general electric large steam turbine rotors. In Life assessment and improvement of turbo-generator rotors for fossil plants (pp. 1–8). New York: Pergamon Press.Google Scholar
- Shih, T., & Clarke, G. (1979). Effects of temperature and frequency on the fatigue crack growth rate properties of a 1950 vintage CrMoV rotor material. In Fracture Mechanics: Proceedings of the Eleventh National Symposium on Fracture Mechanics (vol. 700, p. 125). ASTM International.Google Scholar
- U.S. Energy Information Administration. (2013). Annual energy outlook 2013. Retrieved from http://www.eia.gov.
- U.S. Nuclear Regulatory Commission. (1987). Standard review plan for the review of safety analysis reports for nuclear power plants, LWR edn. Washington, D.C.: US Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation.Google Scholar