A Unified Approach to Turbine Blade Life Prediction

1982 ◽  
Author(s):  
B.L Lewis ◽  
L.R. Beckwith
Keyword(s):  
Turbine Blade ◽  
Life Prediction ◽  
Unified Approach

Life Prediction Method of CC and DS Ni Base Superalloys Under High Temperature Biaxial Fatigue Loading

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Takashi Ogata
Keyword(s):  
Fatigue Life ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Life Prediction ◽  
Compressive Strain ◽  
Prediction Method ◽  
Strain Range ◽  
Fatigue Loading ◽  
Normal Strain ◽  
Biaxial Fatigue

Polycrystalline conventional casting (CC) and directionally solidified (DS) Ni base superalloys are widely used as gas turbine blade materials. It was reported that the surface of a gas turbine blade is subjected to a biaxial tensile-compressive fatigue loading during a start-stop operation, based on finite element stress analysis results. It is necessary to establish the life prediction method of these superalloys under biaxial fatigue loading for reliable operations. In this study, the in-plane biaxial fatigue tests with different phases of x and y directional strain cycles were conducted on both CC and DS Ni base superalloys (IN738LC and GTD111DS) at high temperatures. The strain ratio ϕ was defined as the ratio between the x and y directional strains at 1/4 cycle and was varied from 1 to −1. In ϕ=1 and −1. The main cracks propagated in both the x and y directions in the CC superalloy. On the other hand, the main cracks of the DS superalloy propagated only in the x direction, indicating that the failure resistance in the solidified direction is weaker than that in the direction normal to the solidified direction. Although the biaxial fatigue life of the CC superalloy was correlated with the conventional Mises equivalent strain range, that of the DS superalloy depended on ϕ. The new biaxial fatigue life criterion, equivalent normal strain range for the DS superalloy was derived from the iso-fatigue life curve on a principal strain plane defined in this study. Fatigue life of the DS superalloy was correlated with the equivalent normal strain range. Fatigue life of the DS superalloy under equibiaxial fatigue loading was significantly reduced by introducing compressive strain hold dwell. Life prediction under equibiaxial fatigue loading with the compressive strain hold was successfully made by the nonlinear damage accumulation model. This suggests that the proposed method can be applied to life prediction of the gas turbine DS blades, which are subjected to biaxial fatigue loading during operation.

scholarly journals Coating Life Prediction for Combustion Turbine Blades

1998 ◽  
Author(s):  
Kwai S. Chan ◽  
N. Sastry Cheruvu ◽  
Gerald R. Leverant
Keyword(s):  
Experimental Data ◽  
Turbine Blade ◽  
Cycle Time ◽  
Life Prediction ◽  
Aluminide Coating ◽  
Turbine Blades ◽  
Prediction Method ◽  
Remaining Life ◽  
Degradation Mechanisms ◽  
Useful Life

A life prediction method for combustion turbine blade coatings has been developed by modeling coating degradation mechanisms including oxidation, spallation, and aluminum loss due to inward diffusion. Using this model, the influence of cycle time on coating life is predicted for GTD-111 coated with an MCrAlY, PtAl, or aluminide coating. The results are used to construct a coating life diagram that depicts failure and safe regions for the coating in a log-log plot of number of startup cycles versus cycle time. The regime where failure by oxidation, spallation, and inward diffusion dominates is identified and delineated from that dominated by oxidation and inward diffusion only. A procedure for predicting the remaining life of a coating is developed. The utility of the coating life diagram for predicting the failure and useful life of MCrAlY, aluminide, or PtAl coatings on the GTD-111 substrate is illustrated and compared against experimental data.

A Unified Approach to Solder Joint Life Prediction

2000 ◽  
Author(s):  
Zhengfang Qian ◽  
Ling Shi ◽  
Sheng Liu
Keyword(s):  
Solder Joint ◽  
Life Prediction ◽  
Unified Approach

Fatigue Mechanics: An Assessment of a Unified Approach to Life Prediction

2009 ◽  
pp. 5-5-23 ◽  
Author(s):  
JC Newman ◽  
EP Phillips ◽  
MH Swain ◽  
RA Everett
Keyword(s):  
Life Prediction ◽  
Unified Approach
Sign in / Sign up

Export Citation Format

Share Document