Effect of Changing Principal Stress Axes on Low-Cycle Fatigue Life in Various Strain Wave Shapes at Elevated Temperature

2008 ◽  
pp. 622-622-13 ◽  
Author(s):  
M Ohnami ◽  
M Sakane ◽  
N Hamada
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Principal Stress ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Strain Wave ◽  
Wave Shapes

Low Cycle Fatigue Behavior of Ni-Base Superalloy IN738LC at Elevated Temperature

2011 ◽  
Vol 275 ◽  
pp. 59-62
Author(s):  
Jae Hoon Kim ◽  
Kwon Tae Hwang ◽  
Keun Bong Yoo ◽  
Han Sang Lee
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Strain Energy ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Turbine Blades ◽  
Superior Performance ◽  
Total Strain ◽  
Cycle Fatigue ◽  
Total Strain Energy

High strength nickel-base super alloys have been used in turbine blades for many years because of their superior performance at high temperature. The prediction of fatigue life for superalloys is important for improving the efficiency. In this study, low cycle fatigue tests are performed the variables of total strain range, and room and elevated temperature. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of IN738LC super alloy. The fatigue life is evaluated by the Coffin-Manson equation, also the predicted lives by plastic and total strain energy density are compared with experimental results.

Low Cycle Fatigue of 9-12% Cr Steel at Elevated Temperature: Cyclic Deformation Behavior and Life Assessment

2016 ◽  
Author(s):  
Peng Zhao ◽  
Fu-Zhen Xuan ◽  
De-Long Wu
Keyword(s):  
Fatigue Life ◽  
Elevated Temperature ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Life Assessment ◽  
Control Mode ◽  
Cycle Fatigue ◽  
Wide Range

Fatigue testing for an important turbine rotor material (X12CrMoWVNbN10-1-1 steel) was carried out over a wide range of strain and stress amplitudes at 873K. Particular attention was paid to the effect of control mode on the cyclic deformation behavior and life assessment at elevated temperature. Two main domains were observed depending both on the strain and stress amplitudes, where the effect of control mode was different. In the micro plastic deformation domain, the cyclic softening is slight and there is no clear difference in fatigue behavior between the stress and strain modes. In the plastic damage regime, stress cycling causes more significant softening or damage than strain cycling. The dependence of damage behavior on the evolution of dislocation substructure was focused. On the other hand, it is not possible to use strain based life model to predict fatigue life with the test results under a different control mode. A unified energy-based model is proposed based upon the deformation mechanism and the experimental results, which can assess the low cycle fatigue life with different control modes. The results obtained in this study could have significant implications in the design of structures.

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