Finite element analysis on creep damage

1996 ◽  
Vol 60 (5) ◽  
pp. 781-786 ◽  
Author(s):  
X.N. Wang ◽  
X.C. Wang
2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Mohammad Shafinul Haque ◽  
Calvin Maurice Stewart

The creep deformation and damage evolution of nickel base superalloy (Waspaloy) at 700 °C are studied using the classic Kachanov–Rabotnov (KR) and a recently developed Sin-hyperbolic (Sinh) model. Uniaxial creep deformation and Bridgman rupture data collected from literature are used to determine the model constants and to compare the KR and the Sinh solutions. Finite-element (FE) simulations on a single eight-node element are conducted to validate the accuracy of the FE code. It is observed that KR cannot predict the creep deformation, damage, and rupture life of nickel base superalloys accurately using one set of constants for all the stress levels. The Sinh model exhibits a superior ability to predict the creep behavior using one set of constants for all the stress levels. Finite-element analysis (FEA) on 3D Bridgman notched Waspaloy specimen using the Sinh model is conducted. The results show that the Sinh model when combined with a representative stress equation and calibrated with experimental data can accurately predict the “notch effect” observed in the rupture life of notched specimen. Contour plots of damage evolution and stress redistribution are presented. It is demonstrated that the Sinh model is less stress sensitive, produces unconditional critical damage equal to unity at rupture, exhibits a more realistic damage distribution around the crack tip, and offers better crack growth analysis than KR.


Author(s):  
Chithranjan Nadarajah ◽  
Benjamin F. Hantz ◽  
Sujay Krishnamurthy

This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used to calculate creep stresses and damage for pressure vessel components. Part 1 [1], illustrated the use of isochronous stress strain curves to obtain creep stresses and damages on two simple example problems which were solved using closed form solution. In Part 2, the isochronous method is implemented in finite element analysis to determine creep stresses and damages on pressure vessel components. Various different pressure vessel components are studied using this method and the results obtained using this method is compared time explicit Omega creep model. The results obtained from the isochronous method is found to be in good agreement with the time explicit Omega creep model.


2013 ◽  
Vol 744 ◽  
pp. 205-210 ◽  
Author(s):  
De Zheng Liu ◽  
Qiang Xu ◽  
Zhong Yu Lu ◽  
Dong Lai Xu ◽  
Feng Tan

The preliminary validation of in-house finite element analysis software for creep damage mechanics is reported. The Finite Element Analysis Method and the programme strcuture for creep damage problem were reported elsewhere and the validation conducted so far include plane stress, plane strain, and axisymmetric cases. Furture work is also outlined.


Author(s):  
Ventzislav G. Karaivanov ◽  
Danny W. Mazzotta ◽  
Minking K. Chyu ◽  
William S. Slaughter ◽  
Mary Anne Alvin

Future oxy-fuel and hydrogen-fired turbines promise increased efficiency and low emissions. However, this comes at the expense of increased thermal load from higher inlet temperatures and a change in the working fluid in the gas path, leading to aero-thermal characteristics that are significantly different than those in traditional gas turbines. A computational methodology, based on three-dimensional finite element analysis (FEA) and damage mechanics is presented for predicting the evolution of creep in airfoils in these advanced turbine systems. Information revealed from three-dimensional computational fluid dynamics (CFD) simulations of external heat transfer and thermal loading over a generic airfoil provides detailed local distributions of pressure, surface temperature, and heat flux penetrating through the thermal barrier coated layer. There is an additional mechanical loading due to the centrifugal acceleration of the airfoil. Finite element analysis is then used to predict temperature and stress fields over the domain of the airfoil. The damage mechanics-based creep model uses a scalar damage parameter. This creep model is coupled with finite element analysis to predict the evolution of stress and creep damage over the entire airfoil. Visualization of the creep damage evolution over the airfoil shows the regions that are most susceptible to failure by creep.


1995 ◽  
Vol 117 (2) ◽  
pp. 116-122 ◽  
Author(s):  
Ahmer R. Syed

A model is developed which predicts the creep damage accumulation in solder joints during temperature cycling. The model relates the crack growth rate to the rate of creep energy density dissipated using the C* parameter of nonlinear fracture mechanics for extensive creep damage. For a eutectic tin-lead solder joint, the damage due to both grain boundary sliding and matrix creep is considered. The validity of the model is proved by correlating the predicted fatigue life of solder joints for 84 I/O leadless ceramic chip carriers with the published measured data for a number of test conditions. The published experimental conditions are simulated in a three dimensional, nonlinear, time and temperature dependent finite element analysis. For each test condition, both components of creep energy density, i.e., energy densities because of grain boundary sliding and matrix creep, are determined separately in the finite element analysis. The values are then used to determine the crack growth parameters and predict the crack growth rate in the solder joint using the crack growth model. The predicted results are found to have good correlation with the measured fatigue life for each test condition.


2007 ◽  
Vol 2007 (0) ◽  
pp. 252-253
Author(s):  
Yutaka Toi ◽  
Masakazu Takagaki ◽  
Satoshi Hirose ◽  
Yukio Takahashi

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