scholarly journals A Combined High and Low Cycle Fatigue Model for Life Prediction of Turbine Blades

Materials ◽  
2017 ◽  
Vol 10 (7) ◽  
pp. 698 ◽  
Author(s):  
Shun-Peng Zhu ◽  
Peng Yue ◽  
Zheng-Yong Yu ◽  
Qingyuan Wang
Keyword(s):  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Cycle Fatigue ◽  
Fatigue Model

A Life Prediction Model for Single-Crystal Nickel-Base Alloys Under Low-Cycle Fatigue

2020 ◽  
Author(s):  
Firat Irmak ◽  
Navindra Wijeyeratne ◽  
Taejun Yun ◽  
Ali Gordon
Keyword(s):  
Single Crystal ◽  
Gas Turbine ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Deformation Model ◽  
Cycle Fatigue ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
Prediction Approach

Abstract In the development and assessment of critical gas turbine components, simulations have a crucial role. An accurate life prediction approach is needed to estimate lifespan of these components. Nickel base superalloys remain the material of choice for gas turbine blades in the energy industry. These blades are required to withstand both fatigue and creep at extreme temperatures during their usage time. Nickel-base superalloys present an excellent heat resistance at high temperatures. Presence of chromium in the chemical composition makes these alloys highly resistant to corrosion, which is critical for turbine blades. This study presents a flexible approach to combine creep and fatigue damages for a single crystal Nickel-base superalloy. Stress and strain states are used to compute life calculations, which makes this approach applicable for component level. The cumulative damage approach is utilized in this study, where dominant damage modes are capturing primary microstructural mechanism associated with failure. The total damage is divided into two distinctive modules: fatigue and creep. Flexibility is imparted to the model through its ability to emphasize the dominant damage mechanism which may vary among alloys. Fatigue module is governed by a modified version of Coffin-Manson and Basquin model, which captures the orientation dependence of the candidate material. Additionally, Robinson’s creep rupture model is applied to predict creep damage in this study. A novel crystal visco-plasticity (CVP) model is used to simulate deformation of the alloy under several different types of loading. This model has capability to illustrate the temperature-, rate-, orientation-, and history-dependence of the material. A user defined material (usermat) is created to be used in ANSYS APDL 19.0, where the CVP model is applied by User Programmable Feature (UPF). This deformation model is constructed of a flow rule and internal state variables, where the kinematic hardening phenomena is captured by back stress. Octahedral, cubic and cross slip systems are included to perform simulations in different orientations. An implicit integration process that uses Newton-Raphson iteration scheme is utilized to calculate the desired solutions. Several tensile, low-cycle fatigue (LCF) and creep experiments were conducted to inform modeling parameters for the life prediction and the CVP models.

scholarly journals High-Temperature Low Cycle Fatigue Life Prediction and Experimental Research of Pre-Tightened Bolts

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 828 ◽  
Author(s):  
Qingmin Yu ◽  
Honglei Zhou ◽  
Xudong Yu ◽  
Xiangjin Yang
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Fatigue Model

Bolted connections are widely used in various mechanical structures due to their superior fastening properties. However, vibration and fatigue loads in the structure are likely to cause fatigue failure of the bolted joints, especially those under high temperature, such as in aero-engines. This paper mainly studies the low-cycle fatigue life of the pre-tightened bolts working at a high temperature. A novel test fixture is designed for fatigue tests, and low cycle fatigue tests of pre-tightened bolts are conducted at the temperatures of 550 °C and 650 °C, respectively. Furthermore, a new low cycle fatigue model that is based on the Von Mises equivalent stress/strain criterion is proposed. Meanwhile, the proposed model is used to predict the high-temperature low cycle fatigue life of pre-tightened bolts according to the stress/strain results obtained by finite element analysis. There is good agreement between the experimental results and those obtained by theoretical prediction, which validates the accuracy of the proposed fatigue model. Research results will provide a theoretical basis for the low cycle fatigue life prediction of pre-tightened bolts.

Probability-based service safety life prediction approach of raw and treated turbine blades regarding combined cycle fatigue

2021 ◽  
Vol 110 ◽  
pp. 106513
Author(s):  
Lei Han ◽  
Cao Chen ◽  
Tongyue Guo ◽  
Cheng Lu ◽  
Chengwei Fei ◽  
...  
Keyword(s):  
Life Prediction ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Cycle Fatigue ◽  
Prediction Approach

A modified energy-based low cycle fatigue model for eutectic solder alloy

1999 ◽  
Vol 41 (3) ◽  
pp. 289-296 ◽  
Author(s):  
X.Q Shi ◽  
H.L.J Pang ◽  
W Zhou ◽  
Z.P Wang
Keyword(s):  
Solder Alloy ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Eutectic Solder ◽  
Fatigue Model
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