Turbine Blade Life Prediction Using Fluid-Thermal-Structural Interaction Simulation

2016 ◽  
Author(s):  
I. A. Ubulom ◽  
A. Fien ◽  
A. J. Neely ◽  
K. Shankar
Keyword(s):  
Fatigue Life ◽  
Hysteresis Loop ◽  
Turbine Blade ◽  
Stable Condition ◽  
Cyclic Stress ◽  
Aerodynamic Load ◽  
Temperature Dependent ◽  
Strain Behavior ◽  
Softening Behavior ◽  
Interaction Simulation

In this study a fluid-thermal-structural simulation is performed to investigate cyclic stress-strain behavior and fatigue life of a gas turbine blade. The Hysteresis loop characteristic of the blade is presented under the coupled influence of various loading conditions, aerodynamic, thermal and static centrifugal loadings. Based on the predicted loading behavior, an energy-based method was used to analyze the fatigue and cumulative damage properties of the blade. The predicted hysteresis loop under aerodynamic load was purely of elastic nature and as such tends to assume a Masing behavior at the stable condition. The case for a combined thermal and aeromechanical loading showed a non-Masing behavior, but rather a temperature-dependent material softening behavior. The fatigue life was also estimated based on the energy density approach using the predicted thermal-structural predicted cyclic loops.

Application of the Cyclic Strain Approach to the Fatigue Failure of Ship Structural Details

1987 ◽  
Vol 31 (03) ◽  
pp. 177-185
Author(s):  
Wolfgang Fricke ◽  
Hans Paetzold
Keyword(s):  
Fatigue Life ◽  
Plastic Region ◽  
Steel Structure ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Damage Parameter ◽  
Elastic Plastic ◽  
Strain Behavior ◽  
Structural Details ◽  
The Relationship

The cyclic strain approach is useful for determining the fatigue life of notches strained in the elastic-plastic region. Examples are the flame-cut edges of cutouts in the ship steel structure. After the description of the cyclic stress-strain behavior of the usual mild steel, the individual elements of the approach are described: the probability distribution of load amplitudes, the relationship between load and local elastic-plastic strain, the relationship between the damage parameter and fatigue life, and finally the damage accumulation law. The approach is illustrated by two examples of longitudinal/transverse web intersections. In the first, the predicted life is confirmed by experimental results. The second example shows the approach for complicated load combinations. It is hoped that this paper will contribute to sound and crack-free ship structural details, particularly if unusual loads are applied to well-tried details or if simplified designs are introduced.

Cyclic stress–strain behavior and low cycle fatigue life of cast A356 alloys

2011 ◽  
Vol 33 (12) ◽  
pp. 1600-1607 ◽  
Author(s):  
M.S. Song ◽  
Y.Y. Kong ◽  
M.W. Ran ◽  
Y.C. She
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Cyclic Stress ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Strain Behavior

Statistical analysis of creep behavior in thermoset and thermoplastic composites reinforced with carbon and glass fibers

2020 ◽  
pp. 030932472097663
Author(s):  
Francisco Maciel Monticeli ◽  
Ana Karoline dos Reis ◽  
Roberta Motta Neves ◽  
Luis Felipe de Paula Santos ◽  
Edson Cocchieri Botelho ◽  
...  
Keyword(s):  
Creep Behavior ◽  
Glass Fibers ◽  
Laminated Composite ◽  
Analytical Models ◽  
Thermoplastic Composites ◽  
Temperature Dependent ◽  
Creep Tests ◽  
Thermoset Composites ◽  
Strain Behavior ◽  
Sensitivity Range

The thermoplastic and thermoset laminates reinforced with different fibers generate variations in the laminated composite mechanical behavior. This work aims to analyze thermoplastic and thermoset composites creep behavior with a reduced number of experiments, applying curve-fitting analytical models (Weibull and Findley) and statistical approach (ANOVA, F-test, and SRM) in order to describe creep behavior. Creep tests were carried out using a design of experiments to define parameter levels, aiming to reduce the number of the experiments, keeping reliability relevance. The temperature shows a stronger influence of creep deformation compared with the use of distinct materials. Thermoplastic matrices seem to be more sensitive to deformation, decreasing the reinforcement contribution. On the other hand, the creep resistance of the thermoset matrix conducts a significant contribution of strain behavior for the reinforcement used. The Findley model showed a temperature-dependent response. While, the Weibull-based model exhibits temperature and material-dependence, ensuring a greater sensitivity range of the parameters applied, an essential factor for a more realistic method description.

scholarly journals Effect of Mean Stress on the Fatigue Life Prediction of Notched Fiber-Reinforced 2060 Al-Li Alloy Laminates under Spectrum Loading

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Weiying Meng ◽  
Liyang Xie ◽  
Yu Zhang ◽  
Yawen Wang ◽  
Xiaofang Sun ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Linear Model ◽  
Life Prediction ◽  
Piecewise Linear ◽  
Forecast Accuracy ◽  
Cyclic Stress ◽  
Fatigue Life Prediction ◽  
Fiber Reinforced ◽  
Piecewise Linear Model ◽  
Spectrum Loading

This paper presents a study on the fatigue life prediction of notched fiber-reinforced 2060 Al-Li alloy laminates under spectrum loading by applying the constant life diagram. Firstly, a review on the state of the art of constant life diagram models for the life prediction of composite materials is given, which highlights the effect on the forecast accuracy. Then, the fatigue life of notched fiber-reinforced Al-Li alloy laminates (2/1 laminates and 3/2 laminates) is tested under cyclic stress, which has different stress cycle characteristics (constant amplitude loading and Mini-Twist spectrum loading). The introduced models are successfully realized based on the available experimental data of examined laminates. In the case of Mini-Twist spectrum loading, the effect of the constant life diagram on the life prediction accuracy of examined laminates is studied based on the rainflow-counting method and Miner damage criteria. The results show that the simple Goodman model and piecewise linear model have certain advantages compared to other complex models for the life prediction of notched fiber metal laminates with different structures under Mini-Twist loading. From the engineering perspective, the S-N curve prediction based on the piecewise linear model is most applicable and accurate among all the models.

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