Probabilistic TMF Life Evaluation of a Single Crystal Turbine Blade Concerning Uncertainty Quantification

2018 ◽  
Author(s):  
Xi Liu ◽  
Dianyin Hu ◽  
Bin Zhang ◽  
Rongqiao Wang
Keyword(s):  
Bayesian Inference ◽  
Single Crystal ◽  
Uncertainty Quantification ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Nickel Superalloy ◽  
Probabilistic Framework ◽  
Life Model ◽  
Richardson Extrapolation Method ◽  
Cyclic Damage

Probabilistic-based design can efficiently quantify the risk and improve the reliability of the turbine blade. In this context, a probabilistic framework concerning the uncertainty quantification for the turbine blade’s TMF life based on the cyclic damage accumulation (CDA) method and Bayesian inference is proposed in this study. Firstly, the damage factors in the critical plane are obtained by the finite element method using Walker constitutive model, during which the discretization error is calibrated using Richardson extrapolation method. After that, the probabilistic TMF life model is established using CDA theory, in which the uncertainty of the material parameters is quantified using Bayesian inference. Finally, TMF life prediction on a single crystal nickel superalloy turbine blade is conducted using the probabilistic framework considering uncertainty quantification. The accuracy and validity of the proposed method is revealed by the comparison between the numerical and experimental results of real turbine blades.

The Influence of Turbine Blade Geometry and Process Parameters on the Structure of Zr Modified Aluminide Coatings Deposited by CVD Method on the ZS6K Nickel Superalloy

2013 ◽  
Vol 197 ◽  
pp. 58-63
Author(s):  
Marek Góral ◽  
Maciej Pytel ◽  
Ryszard Filip ◽  
Jan Sieniawski
Keyword(s):  
Chemical Composition ◽  
Turbine Blade ◽  
Process Parameters ◽  
Aluminide Coating ◽  
Turbine Blades ◽  
Leading Edge ◽  
Nickel Superalloy ◽  
Influence Of Process Parameters ◽  
Aluminide Coatings ◽  
Blade Geometry

The Zr modified aluminide coatings is an alternative concept for replacing Pt-modified aluminide bondcoat for thermal barrier coatings. In the paper the influence of process parameters on the chemical composition and the thickness of aluminide coatings will be presented. The zirconia-doped aluminide coating was deposited on turbine blades made from ZS6K nickel superalloy during the low-activity CVD process. In recent work the influence of turbine blade geometry on thickness of coating was observed. The thickest coating was observed on the trailing and leading edge on the blade cross-section. In the conducted research, the light and scanning electron microscopy were used as well as the EDS chemical composition microanalysis.

Aero Engine Test Experience With CMSX-4® Alloy Single-Crystal Turbine Blades

1996 ◽  
Vol 118 (2) ◽  
pp. 380-388 ◽  
Author(s):  
K. P. L. Fullagar ◽  
R. W. Broomfield ◽  
M. Hulands ◽  
K. Harris ◽  
G. L. Erickson ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Turbine Blade ◽  
Hot Corrosion ◽  
Turbine Blades ◽  
Casting Process ◽  
Creep Rupture ◽  
Coating Performance ◽  
Turbine Engine ◽  
Mechanical Fatigue

A team approach involving a turbine engine company (Rolls-Royce), its single-crystal casting facilities, and a superalloy developer and ingot manufacturer (Cannon-Muskegon), utilizing the concepts of simultaneous engineering, has been used to develop CMSX-4 alloy successfully for turbine blade applications. CMSX-4 alloy is a second-generation nickel-base single-crystal superalloy containing 3 percent (wt) rhenium (Re) and 70 percent volume fraction of the coherent γ′ precipitate strengthening phase. Its finely balanced composition offers an attractive range of properties for turbine airfoil applications. In particular the alloy’s combination of high strength in relation to creep-rupture, mechanical and thermal fatigue, good phase stability following extensive high temperature, stressed exposure and oxidation, hot corrosion and coating performance, are attractive for turbine engine applications where engine performance and turbine airfoil durability are of prime importance. The paper details the single-crystal casting process and heat treatment manufacturing development for turbine blades in CMSX-4 alloy. Competitive single-crystal casting yields are being achieved in production and extensive vacuum heat treatment experience confirms CMSX-4 alloy to have a practical production solution heat treat/homogenization “window.” The creep-rupture data-base on CMSX-4 alloy now includes 325 data points from 17 heats including 3630 kg (8000 lb) production size heats. An appreciable portion of this data was machined-from-blade (MFB) properties, which indicate turbine blade component capabilities based on single-crystal casting process, component configuration, and heat treatment. The use of hot isostatic pressing (HIP) has been shown to eliminate single-crystal casting micropores, which along with the essential absence of γ/γ′ eutectic phase, carbides, stable oxide, nitride and sulfide inclusions, results in remarkably high mechanical fatigue properties, with smooth and particularly notched specimens. The Re addition has been shown not only to benefit creep and mechanical fatigue strength (with and without HIP), but also bare oxidation, hot corrosion (sulfidation), and coating performance. The high level of balanced properties determined by extensive laboratory evaluation has been confirmed during engine testing of the Rolls-Royce Pegasus turbofan.

Development of Life Prediction Method of Turbine Blade Using the Theory of Critical Distance

2012 ◽  
Author(s):  
Tetsuya Nakahara ◽  
Yusuke Ueda ◽  
Hiroshi Nakamura
Keyword(s):  
Single Crystal ◽  
Turbine Blade ◽  
Contact Surface ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Prediction Method ◽  
Critical Distance ◽  
Fatigue Tests ◽  
Evaluation Methodology ◽  
Element Analysis

Gas turbine blades mounted dovetail root are subjected to high centrifugal loads and gas forces. This situation causes low cycle fatigue (LCF). Recently, rotating speed and temperature of turbine rotor become higher in order to improve engine performance. To achieve this, it is required to evaluate accurate turbine blade’s LCF life of the contact surface between the blade dovetail root and the disk. However, the estimated blade lives using the peak stress calculated by finite element analysis (FEA) are much shorter than actual life because the stress at contact surface is excessively high. As a result, the blades are designed conservative and the blade’s weight tends to be heavy. Therefore, a more accurate evaluation methodology needs to be established. This study investigates the method to estimate the fatigue strength of dovetail using the theory of critical distance. The theory assumes that fatigue failures would occur due to the representative stress within a specific distance from stress concentration point. Fatigue tests and FEA for the turbine blade dovetail were conducted respectively in this research. The tests were carried out using single crystal nickel-based turbine blades at 600 °C and the fracture lives of dovetail were obtained. FEA was conducted to obtain the stress distributions at dovetail contact surface under testing condition. In this study, the critical distances of the single crystal nickel based alloy were obtained from the notched bar fatigue tests and FEA. Using these results and the theory of critical distance, fatigue lives of dovetail were obtained more accurately.

Structural Perfection of a Single Crystal Nickel-Based CMSX-4 Superalloy

2012 ◽  
Vol 186 ◽  
pp. 151-155 ◽  
Author(s):  
Arkadiusz Onyszko ◽  
Włodzimierz Bogdanowicz ◽  
Jan Sieniawski
Keyword(s):  
Single Crystal ◽  
Turbine Blades ◽  
Nickel Superalloy ◽  
Crystal Form ◽  
High Temperature Creep ◽  
Aircraft Engines ◽  
Structural Perfection ◽  
Columnar Grains ◽  
Bridgeman Method ◽  
Nickel Base

The aircraft engines turbine blades are manufactured from nickel-base superalloys and they are often in a single crystal form. This ensures the best high-temperature creep resistance as compared with blades of equiaxial grains microstructure and of columnar grains microstructure. Turbine blades were manufactured in an ALD Vacuum Technologies furnace. The study has examined structural perfection of single crystal blades obtained by Bridgeman method from CMSX-4 nickel superalloy at various withdrawal rates: 1, 2, 3, 4 and 5mm/min.

The Influence of Crystal Orientation on the Elastic Stresses of a Single Crystal Nickel-Based Turbine Blade

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Michael W. R. Savage
Keyword(s):  
Single Crystal ◽  
Turbine Blade ◽  
Fatigue Resistance ◽  
Crystal Orientation ◽  
Turbine Blades ◽  
Casting Process ◽  
Directionally Solidified ◽  
Element Analysis ◽  
Angle Variation ◽  
Elastic Stresses

Single crystal nickel-based turbine blades are directionally solidified during the casting process with the crystallographic direction [001] aligned with the blade stacking axis. This alignment is usually controlled within 10 deg, known as the Primary angle. The rotation of the single crystal about the [001] axis is generally not controlled and this is known as the Secondary angle. The variation in Primary and Secondary angles relative to the blade geometry means that the stress response from blade to blade will be different, even for the same loading conditions. This paper investigates the influence of single crystal orientation on the elastic stresses of a CMSX-4 turbine blade root attachment using finite element analysis. The results demonstrate an appreciable variation in elastic stress when analyzed over the controlled Primary angle, and are further compounded by the uncontrolled Secondary angle. The maximum stress range will have a direct impact on the fatigue resistance of the turbine blade. By optimizing the Secondary angle variation the elastic stresses can be reduced, giving the potential to enhance the fatigue resistance of the turbine blade.

scholarly journals Effect of Crystal Orientation on Fatigue Failure of Single Crystal Nickel Base Turbine Blade Superalloys

2000 ◽  
Author(s):  
Nagaraj K. Arakere ◽  
Gregory Swanson
Keyword(s):  
Fatigue Life ◽  
Single Crystal ◽  
Turbine Blade ◽  
Fatigue Failure ◽  
Failure Criterion ◽  
Crystal Orientation ◽  
Rocket Engine ◽  
Maximum Shear Stress ◽  
Turbine Blades ◽  
Fe Model

High Cycle Fatigue (HCF) induced failures in aircraft gas turbine and rocket engine turbopump blades is a pervasive problem. Single crystal nickel turbine blades are being utilized in rocket engine turbopumps and jet engines throughout industry because of their superior creep, stress rupture, melt resistance and thermomechanical fatigue capabilities over polycrystalline alloys. Currently the most widely used single crystal turbine blade superalloys are PWA 1480/1493, PWA 1484, RENE’ N-5 and CMSX-4. These alloys play an important role in commercial, military and space propulsion systems. Single crystal materials have highly orthotropic properties making the position of the crystal lattice relative to the part geometry a significant factor in the overall analysis. The failure modes of single crystal turbine blades are complicated to predict due to the material orthotropy and variations in crystal orientations. Fatigue life estimation of single crystal turbine blades represents an important aspect of durability assessment. It is therefore of practical interest to develop effective fatigue failure criteria for single crystal nickel alloys and to investigate the effects of variation of primary and secondary crystal orientation on fatigue life. A fatigue failure criterion based on the maximum shear stress amplitude [Δτmax] on the 24 octahedral and 6 cube slip systems, is presented for single crystal nickel superalloys (FCC crystal). This criterion reduces the scatter in uniaxial LCF test data considerably for PWA 1493 at 1200F in air. Additionally, single crystal turbine blades used in the alternate advanced high-pressure fuel turbopump (AHPFTP/AT) are modeled using a large-scale 3D finite element (FE) model. This FE model is capable of accounting for material orthotrophy and variation in primary and secondary crystal orientation. Effects of variation in crystal orientation on blade stress response are studied based on 297 FE model runs. Fatigue lives at critical points in the blade are computed using FE stress results and the failure criterion developed. Stress analysis results in the blade attachment region are also presented. Results presented demonstrates that control of secondary and primary crystallographic orientation has the potential to significantly increase a component’s resistance to fatigue crack growth without adding additional weight or cost.

Gamma Prime Crystal Lattice Orientation of Turbine Blades of the Single Crystal Nickel Based CMSX-4 Superalloy

2013 ◽  
Vol 203-204 ◽  
pp. 169-172 ◽  
Author(s):  
Arkadiusz Onyszko
Keyword(s):  
Single Crystal ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Nickel Superalloy ◽  
Vacuum Furnace ◽  
Lattice Orientation ◽  
Aerospace Materials ◽  
Gamma Prime ◽  
University Of Technology ◽  
Development Laboratory

The paper attempts to determine the changes in the γ’ lattice orientation of aircraft engine turbine blades made of the CMSX-4 single crystal nickel superalloy. The solidification of a hollow assembly structure for 2 various blades was carried out by the Bridgman method at the Research and Development Laboratory for Aerospace Materials at Rzeszow University of Technology using an ALD Vacuum Technologies vacuum furnace. Ceramic moulds made of Al2O3 were used. The alloy temperature during casting into the mould amounted to 1550°C. The specimens for Laue method tests were cut out from the blades at withdrawal rates of 3 and 4 mm/min.

Modeling of Unidirectional Growth in a Single Crystal Turbine Blade Casting

2006 ◽  
Vol 508 ◽  
pp. 111-116 ◽  
Author(s):  
Qing Yan Xu ◽  
Bai Cheng Liu ◽  
Zuo Jian Liang ◽  
Jia Rong Li ◽  
Shi Zhong Liu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Directional Solidification ◽  
Turbine Blade ◽  
Defect Formation ◽  
Turbine Blades ◽  
Solidification Process ◽  
Nickel Base Superalloy ◽  
Transversal Section ◽  
Nickel Base ◽  
Blade Casting

Single crystal superalloy turbine blade are widely used in aero-engineering. However, there are often grain defects occurring during the fabrication of blade by casting. It is important to study the formation of microstructure related defects in turbine blades. Single crystal blade sample castings of a nickel-base superalloy were produced at different withdrawal rates by the directional solidification process and investment casting. There was a difference between the microstructure morphology at the top part of the turbine blade sample castings and the one at the bottom. Higher withdrawal rates led to more differences in the microstructure and a higher probability of crystallographic defect formation such as high angle boundaries at locations with an abrupt change of the transversal section area. To further investigate the formation of grain defects, a numerical simulation technique was used to predict the crystallographic defects occurring during directional solidification. The simulation results agreed with the experimental ones.

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