Paper Title :Fatigue Life Prediction of Steam Turbine Blades with Three-Dimensional Structural Mistuning
Author :Dawood A Desai, Makgwantsha H Mashiachidi
Article Citation :Dawood A Desai ,Makgwantsha H Mashiachidi ,
(2024 ) " Fatigue Life Prediction of Steam Turbine Blades with Three-Dimensional Structural Mistuning " ,
International Journal of Mechanical and Production Engineering (IJMPE) ,
pp. 8-16,
Volume-12,Issue-11
Abstract : Low-Pressure steam turbines commonly experience premature blade and disk failures due to stress concentrations
at the blade root area of its bladed disk. Hence, inspired by such problems encountered with steam turbine blades, this
research presents a numerical methodology for the life prediction of mistuned steam turbine blades caused by variations in
blade geometry as such studies have not yet been contemplated. Steam turbine blades are typically subjected to steam flow
bending, centrifugal loading, vibration and structural mistuning. Based on these factors, a simplified, scaled-down, steam
turbine bladed disk model was developed using finite element software. Acquisition of the vibration characteristics and
steady-state stress response of the disk models was performed through finite element analysis. Thereafter, numerical stress
distributions were acquired, and the model was subsequently exported to Fe-Safe software for fatigue life calculations based
on centrifugal and harmonic sinusoidal pressure loading. Subsequently, Monte Carlo simulations were performed in
Companion software to determine the probabilistic fatigue life for 17 cases of steam turbine-bladed disks which was defined
by selecting mistuning (geometry variation) percentages as the random variables. Thereafter, the obtained results were
validated by the discrete results with a good level of correlation being achieved between them. The results showed that the
fatigue life is most sensitive to changes in blade thickness, followed by its length, and then the width, in this order. Hence,
the developed methodology was proven reliable and can be successfully used to predict the fatigue life of mistuned steam
turbine blades.
Keywords - Blade Geometric Variation, Turbine Blade Mistuning, Finite Element Analysis, Fatigue
Type : Research paper
Published : Volume-12,Issue-11
Copyright: © Institute of Research and Journals
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Published on 2025-03-17 |
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