Fatigue life assessment of a low pressure steam turbine blade during transient resonant conditions using a probabilistic approach

Booysen, Christopher; Heyns, P.S.; Hindley, Michael P.; Scheepers, Ronnie

doi:10.1016/j.ijfatigue.2014.11.007

Cited by 34 publications

(41 citation statements)

References 25 publications

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“…In practice, LCF analysis of HPT discs is performed by using deterministic approaches based on small sample tests. However, researches in Chen et al, Booysen et al, and Hudak et al pointed out that the variability of engine component usages might result into more than 6 times of the variability in fatigue life and even 100 times more variability in the failure probability at a given life. Thus, systematically dealing with multiple sources of uncertainty in fatigue significantly affects the performance in defining morphology and material of engine components, as well as the robustness of fatigue design.…”

Section: Introductionmentioning

confidence: 99%

Fatigue reliability assessment of turbine discs under multi‐source uncertainties

Zhu

Liu

Zhou

et al. 2018

Fatigue Fract Eng Mat Struct

174

100

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Hot section components of aircraft engines like high pressure turbine (HPT) discs usually operate under complex loadings coupled with multi‐source uncertainties. The effect of these uncertainties on structural response of HPT discs should be accounted for its fatigue life and reliability assessment. In this study, a probabilistic framework for fatigue reliability analysis is established by incorporating FE simulations with Latin hypercube sampling to quantify the influence of material variability and load variations. Particularly, variability in material response is characterized by combining the Chaboche constitutive model with Fatemi‐Socie criterion. Results from fatigue reliability and sensitivity analysis of a HPT disc indicated that dispersions of basic variables {},,ρω1σf′ must be taken into account for its fatigue reliability analysis. Moreover, the proposed framework based on the strength‐damage interference provides more reasonably correlations with its field number of flights rather than the load‐life interference one.

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Section: Introductionmentioning

confidence: 99%

Fatigue reliability assessment of turbine discs under multi‐source uncertainties

Zhu

Liu

Zhou

et al. 2018

Fatigue Fract Eng Mat Struct

174

100

View full text Add to dashboard Cite

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“…On the other hand, the damper was laterally loaded with 0.001 to mimic the effects of centrifugal force. These loading parameters were computed based on the work Booysen et al [16] on fatigue assessment of low pressure steam turbine blades. The heat losses due to convection were modelled using convection coefficient of 30 .…”

Section: Finite Element Modellingmentioning

confidence: 99%

Application of frictional heat signatures for prediction of structural vibrational characteristics

Talai¹,

Desai²,

Heyns³

2016

Heat Transfer XIV: Simulation and Experiments in Heat Transfer and Its Applications

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Frictional damping of vibrating components such as turbomachinery blades, generally result in a temperature increase at the blade-lacing wire interface due to blade harmonic motion during operation. Interestingly, studies have shown that temperature is amongst the most common indicators of structural health of a dynamic component. Nevertheless, its application to measurement of vibration characteristics has not yet been contemplated and thus relatively unique. Hence, the aim of this work is to develop a novel technique for acquiring structural vibrational characteristics from frictional heat signatures. To facilitate this, an experimentally validated finite element model (FEM) was developed. The skillful manipulation of heat conduction equations and a finite difference approach; successfully identified the vibration behavior. The implications and benefits of the developed technique for structural integrity and condition monitoring applications are numerous, for example; the early detection of structural defects. Furthermore, this approach has great potential of overcoming most of the limitations experienced with conventional methods such as strain gauging which encounter fatigue during vibration measurement and may thus compromise measurements.

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“…Hence, as damping bearing properties influence significantly the turbine's levels of vibration, an optimum design could be adopted by minimizing the imbalances in operational rotation speeds. Accumulated knowledge of the dynamic behavior of the steam turbine system, could be later implemented in order to evaluate stability or instability states, fatigue growth in the turbine blades, changes in the damping of the bearing system and perform necessary scheduled optimal and cost-effective maintenance strategies (Bavastri et al, 2008;Booysen et al, 2015;Plesiutschnig et al, 2016). Additionally, upon a series of scheduled experimental data collection, a permanent output-only vibration Structural Health Monitoring system could be installed and even a proper dynamic balancing could be investigated and designed.…”

Section: Introductionmentioning

confidence: 99%

Integrated Reverse Engineering Strategy for Large-Scale Mechanical Systems: Application to a Steam Turbine Rotor

Αραϊλόπουλος

Giagopoulos

Zacharakis

et al. 2018

Front. Built Environ.

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An integrated reverse engineering methodology is proposed for a large-scale fully operational steam turbine rotor, considering issues that include developing the CAD and FE model of the structure, as well as the applicability of model updating techniques based on experimental modal analysis procedures. First, using an integrated reverse engineering strategy, the digital shape of the three sections of a steam turbine rotor was designed and the final parametric CAD model was developed. The finite element model of the turbine was developed using tetrahedral solid elements resulting in fifty-five million DOFs. Imposing impulsive loading in a free-free state, measured acceleration time histories were used to obtain the dynamic responses and identify the modal characteristics of each section of the complete steam turbine. Experimentally identified modal modes and modal frequencies compared to the FE model predicted ones constitute the actual measure of fit. CMA-ES optimization algorithm is then implemented in order to finely tune material parameters, such as modulus of elasticity and density, in order to best match experimental and numerical data. Comparing numerical and experimental results verified the reliability and accuracy of the applied methodology. The identified finite element model is representative of the initial structural condition of the turbine and is used to develop a simplified finite element model, which then used for the turbine rotordynamic analysis. Accumulated knowledge of the dynamic behavior of the specific steam turbine system, could be implemented in order to evaluate stability or instability states, fatigue growth in the turbine blades, changes in the damping of the bearing system and perform necessary scheduled optimal and cost-effective maintenance strategies. Additionally, upon a series of scheduled experimental data collection, a permanent output-only vibration SHM system could be installed and even a proper dynamic balancing could be investigated and designed.

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Fatigue life assessment of a low pressure steam turbine blade during transient resonant conditions using a probabilistic approach

Abstract: This paper presents a sequential approach used in fatigue life prediction of a low pressure

Cited by 34 publications

References 25 publications

Fatigue reliability assessment of turbine discs under multi‐source uncertainties

Fatigue reliability assessment of turbine discs under multi‐source uncertainties

Application of frictional heat signatures for prediction of structural vibrational characteristics

Integrated Reverse Engineering Strategy for Large-Scale Mechanical Systems: Application to a Steam Turbine Rotor

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