A continuum damage mechanics model on low cycle fatigue life assessment of steam turbine rotor

2001 ◽  
Vol 78 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Jian Ping Jing ◽  
Yi Sun ◽  
Song Bo Xia ◽  
Guo Tai Feng
Keyword(s):  
Fatigue Life ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Continuum Damage Mechanics ◽  
Turbine Rotor ◽  
Life Assessment ◽  
Continuum Damage ◽  
Cycle Fatigue ◽  
Mechanics Model ◽  
Fatigue Life Assessment

Assessment of Low Cycle Fatigue Life of Steam Turbine Rotor Based on a Thermodynamic Approach

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Yong-Jian Sun ◽  
Li-Sheng Hu
Keyword(s):  
Fatigue Life ◽  
Steam Turbine ◽  
Nonlinear Model ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Continuum Damage Mechanics ◽  
Turbine Rotor ◽  
Cyclic Stress ◽  
Cycle Fatigue ◽  
Steam Turbine Rotor

A new nonlinear model is proposed to assess the low cycle fatigue life of a 300 MW steam turbine rotor. Manson-Coffin equation and cyclic stress-strain relationship are employed to eliminate the unmeasured parameters, so all the parameters in model are measurable. Through comparison with that from the linear accumulation theory and continuum damage mechanics theory the results show this new nonlinear model describes the damage accumulation well and precisely in accordance with the practical test data. This approach supplies a new way to assess the damage of steam turbine rotor with satisfactory precision in engineering.

Continuum damage mechanics application in low-cycle thermal fatigue

2012 ◽  
Vol 22 (2) ◽  
pp. 285-300 ◽  
Author(s):  
M Mashayekhi ◽  
A Taghipour ◽  
A Askari ◽  
M Farzin
Keyword(s):  
Fatigue Life ◽  
Thermal Fatigue ◽  
Damage Evolution ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Isothermal Condition ◽  
Continuum Damage Mechanics ◽  
Life Assessment ◽  
Continuum Damage ◽  
Fatigue Damage Accumulation

In this article, a fatigue model for low-cycle thermal fatigue formulated in a continuum damage mechanics framework is presented. The model is based on a unified damage law presented by Lemaitre for low-cycle fatigue, which has been extended to low-cycle thermal fatigue. The temperature dependencies of material parameters are considered in the damage evolution integration to take the non-isothermal condition of loading into account. This model considers the stress triaxiality and non-linearity of damage evolution, and it is developed to a fatigue damage accumulation rule in which the load sequence effect is also included. The stabilized structural response under thermomechanical loading motivates the use of uncoupled analysis approach making the model a fast tool suitable for design purposes in the costly and time-consuming field of thermomechanical fatigue life assessment. To demonstrate the capability and ease of use of this model for real industrial applications, the low-cycle thermal fatigue life of a stainless steel engine exhaust manifold which is in an early stage of design is assessed.

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