An assessment of thermo-mechanically induced fatigue damage of a steam turbine shaft

A multi-axial continuum damage mechanics (CDM) model was proposed to calculate the multi-axial creep–fatigue damage of a high temperature component. A specific outer cylinder of a 1000 MW supercritical steam turbine was used in this study, and the interaction of the creep and fatigue behavior of the outer cylinder was numerically investigated under a startup–running–shutdown process. To this end, the multi-axial stress–strain behavior of the outer cylinder was numerically studied using Abaqus. The in-site measured temperatures were provided to validate the heat transfer coefficients, which were used to calculate the temperature field of the outer cylinder. The multi-axial mechanics behavior of the outer cylinder was investigated in detail, with regard to the temperature, Mises stress, hydrostatic stress, multi-axial toughness factor, multi-axial creep strain, and damage. The results demonstrated that multi-axial mechanics behavior reduced the total damage.

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Investigation of hold period influence on residual fatigue live in steam turbine shaft design

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/461/1/012072 ◽

2018 ◽

Vol 461 ◽

pp. 012072

Author(s):

M Rund ◽

R Procházka ◽

J Džugan ◽

P Konopík ◽

M Nesládek ◽

...

Keyword(s):

Steam Turbine ◽

Hold Period ◽

Turbine Shaft ◽

Residual Fatigue

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Influence of Creep on Low-Cycle Fatigue Life Assessment of Ultra-Supercritical Steam Turbine Rotor

Volume 7A: Structures and Dynamics ◽

10.1115/gt2014-26757 ◽

2014 ◽

Author(s):

W. Z. Wang ◽

J. H. Zhang ◽

H. F. Liu ◽

Y. Z. Liu

Keyword(s):

High Temperature ◽

Steam Turbine ◽

Fatigue Damage ◽

Low Cycle Fatigue ◽

Turbine Rotor ◽

High Temperature Creep ◽

Cycle Fatigue ◽

Term Operation ◽

Start Up

Linear damage method is widely used to calculate low-cycle fatigue damage of turbine rotor in the long-term operation without fully considering the interaction between creep and low cycle fatigue. However, with the increase of steam turbine pressure and temperature, the influence of high-temperature creep on the strain distribution of turbine rotor becomes significant. Accordingly, the strain for each start-up or shut-down process is different. In the present study, the stress and strain during 21 iterations of continuous start-up, running and shut-down processes was numerically investigated by using the finite element analysis. The influence of high-temperature creep on low cycle fatigue was analyzed in terms of equivalent strain, Mises stress and low cycle fatigue damage. The results demonstrated that the life consumption of turbine rotor due to low cycle fatigue in the long-term operation of startup, running and shutdown should be determined from the full-time coverage of the load of turbine rotor.

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Problems and Result of Recent Research in the Heat Indication Test of the Steam Turbine Shaft Forgings

Journal of the Society of Mechanical Engineers ◽

10.1299/jsmemag.64.507_621 ◽

1961 ◽

Vol 64 (507) ◽

pp. 621-628

Author(s):

Hideo SHIMODA ◽

Shinsaku ONODERA ◽

Akira TOKUDA

Keyword(s):

Steam Turbine ◽

Turbine Shaft ◽

Indication Test

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Evaluation of Fatigue Damage by X-Ray Diffraction Technique of Steam Turbine Rotor Steels at Elevated Temperatures

Volume 5: High Pressure Technology; Nondestructive Evaluation Division; Student Paper Competition ◽

10.1115/pvp2009-77386 ◽

2009 ◽

Author(s):

Jaroslav Fiala ◽

Vaclav Mentl ◽

Vladislav Kolarik ◽

Michal Chocholousek

Keyword(s):

Mechanical Properties ◽

Steam Turbine ◽

Fatigue Damage ◽

Elevated Temperatures ◽

Turbine Rotor ◽

Residual Lifetime ◽

X Ray Diffraction ◽

Time Service ◽

X Ray ◽

Steam Turbine Rotor

In many industrial applications materials are subjected to degradation of mechanical properties as a result of real service conditions. The assessment of the remaining lifetime of components and structures is commonly based on correlated procedures including numerous destructive, non-destructive and mathematical techniques that should guarantee reasonable precise assessment of the current damage extent of materials in question and the remnant lifetime assessment. The assessment of the remaining lifetime by X-ray diffraction technique is based on the fact that mechanical properties of the most materials depend strongly on crystallite size and orientation of ingredients, which are the crucial parameters for the determination of the ageing state and the prediction of residual lifetime of the components. X-ray diffraction technique proved to be useful as a tool for the assessment of material degradation extent after a long-time service. Framework 5 project “XPECTION” [1] was dealing with this task with respect to high temperature creep degradation of boiler tube steels. In this presentation, the X-ray diffraction technique was applied to reveal subtle details of the microstructural changes induced by fatigue. Several steam turbine rotor steels were fatigue tested at elevated temperatures up to 600°C at strain control regime. After the tests, the X-ray diffraction method was used to correlate the extent of fatigue damage with the X-Ray diffraction patterns to be able to assume the life-time exhaustion caused by fatigue loading in service.

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