Tribology and Materials | Volume 2 | Issue 4 | 2023 | 172-180
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https://doi.org/10.46793/tribomat.2023.017
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Fatigue life prediction of turbine blades with geometric imperfections made of stainless steel
Makgwantsha Hermelton Mashiachidi
,
Dawood A. Desai
Faculty of Engineering and the Built Environment, Tshwane University of
Technology, Pretoria, South Africa
Abstract: This research addresses critical challenges faced by
steam turbine blades, particularly in low-pressure (LP) turbines, where
premature failures are common due to stress concentrations at the blade
root area. The study introduces a numerical methodology aimed at
predicting the life of mistuned steam turbine blades, with a focus on
variations in blade geometry which have received limited exploration in
existing literature. A simplified, scaled-down mistuned steam turbine
bladed disc model was developed using Abaqus finite element software.
Acquisition of steady-state stress response of the disc models was
performed through finite element analysis (FEA). Thereafter, numerical
stress distributions were obtained. Subsequently, within Companion
software, a Monte Carlo simulation-based probabilistic approach was
applied to evaluate and quantify uncertainties in fatigue life for 17
cases. This analysis considered an accepted manufacturing percentage
scatter of ± 5 % for the steam turbine bladed disc. That was conducted
by selecting mistuning (geometry variation) percentages as the random
variables. The methodology demonstrated reliability, correlating well
with literature-based and discrete fatigue life results. This study
establishes the potential for accurately predicting the fatigue life of
mistuned steam turbine blades using the developed methodology.
Keywords:
geometric variation, low-pressure, finite element analysis, fe-safe, fatigue failure, stainless steel, material properties.
Received: 12-09-2023, Revised: 30-10-2023, Accepted: 31-10-2023
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt,
and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.
Abstract: This research addresses critical challenges faced by steam turbine blades, particularly in low-pressure (LP) turbines, where premature failures are common due to stress concentrations at the blade root area. The study introduces a numerical methodology aimed at predicting the life of mistuned steam turbine blades, with a focus on variations in blade geometry which have received limited exploration in existing literature. A simplified, scaled-down mistuned steam turbine bladed disc model was developed using Abaqus finite element software. Acquisition of steady-state stress response of the disc models was performed through finite element analysis (FEA). Thereafter, numerical stress distributions were obtained. Subsequently, within Companion software, a Monte Carlo simulation-based probabilistic approach was applied to evaluate and quantify uncertainties in fatigue life for 17 cases. This analysis considered an accepted manufacturing percentage scatter of ± 5 % for the steam turbine bladed disc. That was conducted by selecting mistuning (geometry variation) percentages as the random variables. The methodology demonstrated reliability, correlating well with literature-based and discrete fatigue life results. This study establishes the potential for accurately predicting the fatigue life of mistuned steam turbine blades using the developed methodology.
Keywords: geometric variation, low-pressure, finite element analysis, fe-safe, fatigue failure, stainless steel, material properties.
Received: 12-09-2023, Revised: 30-10-2023, Accepted: 31-10-2023
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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license, which allows users to distribute, remix, adapt, and build upon the material in any medium or format for non-commercial purposes only, and only so long as attribution is given to the creator.