A Comparative Study of Local and Nonlocal Domain Integration for XFEM Based Stress Intensity Factor Extraction for Fatigue Life Prediction

2016 ◽  
Author(s):  
Xiang Ren ◽  
Ali Sadeghirad ◽  
Neethi Simon ◽  
Jim Lua
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Comparative Study ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Domain Integration

scholarly journals Fatigue life prediction under mixed-mode loading using equivalent stress intensity factor models

2018 ◽  
Vol 172 ◽  
pp. 03005 ◽  
Author(s):  
S. Sajith ◽  
K.S.R. K. Murthy ◽  
P.S. Robi
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Mixed Mode ◽  
Life Prediction ◽  
Damage Tolerance ◽  
Equivalent Stress ◽  
Fatigue Life Prediction

Damage tolerance principles are widely used to assess the structural integrity and failure of engineering components. The advances in numerical simulation techniques facilitate the prediction of fatigue life of engineering component, which is essential in damage tolerance design. For the components under mixed mode (I/II) loading, the fatigue crack growth and life is predicted by using a modified form of Paris' law along with the equivalent stress intensity factor (ΔKeq). Numerous ΔKeq models are available for correlating the equivalent stress intensity factor range and the fatigue crack growth rate. The knowledge of proper ΔKeq model is essential for the accurate fatigue life estimation. In this work, the authors numerically assess the performance of ΔKeq models in mixed mode fatigue life prediction with the help of published experimental mixed mode data.

Probabilistic considerations for growth and detection of cracks from rivet holes in a lap joint

2013 ◽  
Vol 117 (1193) ◽  
pp. 727-740 ◽  
Author(s):  
M. L. Cohen ◽  
J. D. Achenbach
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Life Prediction ◽  
Bayes Theorem ◽  
Initial Crack ◽  
Probability Of Detection ◽  
Fatigue Life Prediction ◽  
Lap Joint ◽  
Paris Law

AbstractIn this paper, probabilistic considerations are introduced in a model for fatigue life prediction for a riveted lap joint using Paris’ law. Initial crack sizes are distributed according to a truncated lognormal distribution, which is chosen to avoid known complications due to Paris’ law. The stress intensity factor for a single rivet hole is calculated, and is generalized to a lap joint. The probability of the existence of a crack in two domains of interest are evaluated, and the effect of a single inspection, modeled using the Probability of Detection, is studied. Additionally, the probability of detection concept is extended by linking it to applied stress and number of elapsed cycles using Bayes’ theorem and ramifications are explored.

Effect of Size and Location of a Weld Defect on Fatigue Life for Argon-Arc Welded Titanium Alloy Joint

2008 ◽  
Vol 33-37 ◽  
pp. 121-128 ◽  
Author(s):  
J.Z. Liu ◽  
Xue Ren Wu ◽  
L.F. Wang ◽  
B.R. Hu ◽  
B. Chen
Keyword(s):  
Stress Intensity Factor ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Life Prediction ◽  
Initial Crack ◽  
Stress Intensity Factor Range ◽  
Weld Defect ◽  
Plasticity Induced Crack Closure

Analytical studies were made on effect of size and location of a weld defect on fatigue life for argon-arc welded titanium alloy joint. In the analyses, a weld defect was assumed as an initial crack, and the crack growth life was taken as total fatigue life. By using the Isida and Noguchi’s stress intensity factor solution for a plate containing an embedded elliptical subsurface crack under tension, the life prediction code FASTRAN3.9 was revised. A small crack methodology based on the plasticity-induced crack-closure concept and the effective stress intensity factor range, Keff , was used to predict the total fatigue life of welded joint, and to study the effect of the size and location of weld defect on fatigue life by means of the revised FASTRAN3.9 code. Limited amounts of experimental data were used to make comparison with the predictions. The predicted fatigue lives are in reasonable agreement with experiments, and the effect of both the size and location of the weld defect on fatigue life was found to be significant.

scholarly journals Effect of Pre-Corrosion Pits on Residual Fatigue Life for 42CrMo Steel

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2130 ◽  
Author(s):  
Dezheng Liu ◽  
Yan Li ◽  
Xiangdong Xie ◽  
Jing Zhao
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Life ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Research Work ◽  
Residual Fatigue Life ◽  
42Crmo Steel ◽  
Regression Formula ◽  
Residual Fatigue ◽  
Corrosion Pits

The effect of pre-corrosion pits on residual fatigue life for the 42CrMo steel (American grade: AISI 4140) is investigated using the accelerated pre-corrosion specimen in the saline environment. Different pre-corroded times are used for the specimens, and fatigue tests with different loads are then carried out on specimens. The pre-corrosion fatigue life is studied, and the fatigue fracture surfaces are examined by a surface profiler and a scanning electron microscope (SEM) to identify the crack nucleation sites and to determine the size and geometry of corrosion pits. Moreover, the stress intensity factor varying with corrosion pits in different size parameters is analyzed based on finite element (FE) software ABAQUS to derive the regression formula of the stress intensity factor. Subsequently, by integrating the regression formula with the Paris formula, the residual fatigue life is predicted and compared with experimental results, and the relationship of the stress intensity factor, pit depth, and residual fatigue life are given under different corrosion degrees. The fatigue life predicted by the coupled formula agrees well with experiment results. It is observed from the SEM images that higher stress amplitude and longer pre-corroded time can significantly decrease the residual fatigue life of the steel. Additionally, the research work has brought about the discovery that the rate of crack extension accelerates when the crack length increases. The research in this paper also demonstrates that the corrosion pit size can be used as a damage index to assess the residual fatigue life.

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