HCF, LCF and creep life analysis of a generic LRE turbine blade

2022 ◽  
Author(s):  
Jörg R. Riccius ◽  
Evgeny B. Zametaev
Keyword(s):  
Turbine Blade ◽  
Creep Life ◽  
Life Analysis

The Effects of Cooling Holes on the Creep Life in a Modeling Specimen of Single Crystal Air-Cooled Turbine Blade

2011 ◽  
Vol 284-286 ◽  
pp. 1678-1683 ◽  
Author(s):  
Da Shun Liu ◽  
Bai Zhi Wang ◽  
Zhi Xun Wen ◽  
Zhu Feng Yue
Keyword(s):  
Single Crystal ◽  
Turbine Blade ◽  
Damage Model ◽  
Creep Damage ◽  
Creep Life ◽  
Damage Development ◽  
User Subroutine ◽  
Initial Rupture ◽  
Creep Deformations ◽  
Sem Analyses

This paper presents the study of the influences of cooling holes on the creep life behavior in the modeling specimen of single crystal cooling turbine blade at high temperature. Thin-walled cylindrical specimens with holes are tested to model the air-cooled turbine blade. Specimens without holes are also studied to make comparisons. Experimental results show that at 900°C, the creep lives of specimens with holes are longer than those of specimens without holes. Scanning Electron Microscopy (SEM) analyses reveal that creep deformations occur firstly around the cooling holes and finally rupture at the region with low stress and strain. Finite element analyses are used to study the creep damage development by a K-R damage model which has been implemented into the Abaqus user subroutine (UMAT). Simulation results show that stress concentration and redistribution occur around the cooling holes during the creep development. It is also shown that the maximum strain and stress are around the cooling holes which are the initial rupture region in the experiments.

Continuum Damage Mechanics and Creep Life Analysis

1999 ◽  
Vol 67 (1) ◽  
pp. 193-196 ◽  
Author(s):  
G. J. Rodin
Keyword(s):  
Damage Mechanics ◽  
Continuum Damage Mechanics ◽  
Continuum Damage ◽  
Creep Life ◽  
Mechanics Model ◽  
Brittle Solids ◽  
Life Analysis

It is shown that the original continuum damage mechanics model of Kachanov is better suited for creep life analysis of creep-brittle solids and structures than continuum damage mechanics models that take into account damage-induced softening. [S0021-8936(00)03001-4]

Probabilistic Life Assessment of Turbine Vanes

2011 ◽  
Author(s):  
Alexander N. Arkhipov ◽  
Yevgeny E. Krasnovskiy ◽  
Igor V. Putchkov
Keyword(s):  
Mechanical Properties ◽  
Gas Turbine ◽  
Material Properties ◽  
Field Data ◽  
Life Assessment ◽  
Creep Life ◽  
Thermal Boundary Conditions ◽  
Life Distributions ◽  
Manufacturing Tolerances ◽  
Life Analysis

Life of a gas turbine vane generally depends on different factors such as scatter of material properties, load variation and manufacturing tolerances. However, deterministic finite element (FE) life analysis gives just a discrete value typically based on the nominal or worst case conditions. It precludes considering sensitivity to the input parameters and obtaining the expected life range. To consider the possible variations of the input parameters from their nominal values, a probabilistic approach has been applied to compute the LCF (Low Cyclic Fatigue) and creep life distributions for the uncooled vane. The deterministic 3D FE life assessment of the gas turbine components is based on the input data such as physical and mechanical properties of the base material and coating at operating temperatures, nominal geometry of the component, thermal and mechanical loadings. Each of the above mentioned inputs has its own scatter band characterized either by average and minimum values of mechanical properties (tensile strength, LCF, creep) or by variations of manufacturing tolerances; thermal boundary conditions and gas pressure distribution. The probabilistic life analysis has been performed in order to assess individual impact of each input on vane’s life scatter. LCF and creep life distributions as well as variation of the base metal oxidation layer thickness have been obtained for each scatter factor and for their overall contribution. It is seen from results that LCF and creep lives of the analyzed vane have been influenced mainly by material properties and secondarily by OTDF (hot gas temperature variation in the circumferential direction) and uncertainties of thermal boundary conditions, which depended on the operation conditions of the engine. Manufacturing tolerances and alternation of ambient air temperature in the compressor intake have the lowest impact. The derived model is useful for the risk analysis or maintenance planning. For instance, it has been shown how probability of small fatigue crack indication in one vane can be extended onto the overall probability for the failure detection of n vanes at the stator stage during regular inspection. The probability of micro crack growth due to creep after the determined amount of operating hours for the single vane may be also redefined into the overall stage probability for the detection of n such vanes. To perform validation, normalized field data have been used for comparison with the analytical predictions. Good correlations between the field data and analytical predictions have been shown.

Life Assessment of Gas Turbine Blades Under Creep Failure Mechanism Considering Humidity

2018 ◽  
Author(s):  
Bita Soltan Mohammad Lou ◽  
Mohammad Pourgol-Mohammad ◽  
Mojtaba Yazdani
Keyword(s):  
Gas Turbine ◽  
Failure Mechanism ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Prediction Models ◽  
Turbine Blades ◽  
Life Assessment ◽  
Creep Life ◽  
Creep Failure ◽  
Design Assessment

Gas turbines are the most important components in thermal power plants, and these components such as turbine has been studied carefully. Gas turbine components operate predominantly under elevated temperature and high stress, and consequently gradual deformation becomes temporally inevitable. In turbine blades, creep is common failure mechanism, and it is an important factor for design assessment. The gas turbine blade is a component operating at high elevated temperatures, requiring a cooling systems to reduce the temperature. Common power enhancement approach is to spray water into compressor, and it is how humidity becomes an important factor in creep failure mechanism. The humidity variability results in temperature level change during the turbine operation, potentially affecting the blades creep life. In this paper, first different creep life prediction models were classified, and then a new model is proposed for creep life considering humidity based on Arrhenius equation. In our study, failure criterion is rupture. As a case study, the creep life of Nimonic-90 alloy turbine blade was predicted using proposed method and compared with FEA results which collected by literature surveys. Proposed model is capable of predicting creep life with only knowing dry temperature (WAR = 0), and there is no need to measure blade temperature variation during operation. The influence of humidity (%WAR) were studied on turbine blades creep life, and results show that creep life of turbine blade increase with increasing humidity percentage.

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