Constraint Effects on the Prediction of Fatigue Life of Surface Flaws

1983 ◽  
Vol 105 (3) ◽  
pp. 215-218 ◽  
Author(s):  
M. Jolles
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Stress Field ◽  
Crack Growth ◽  
Crack Closure ◽  
Growth Analysis ◽  
Crack Shape ◽  
Surface Flaws ◽  
Constraint Effects

The effects of the variation of stress field triaxiality on the prediction of the fatigue growth of semielliptic surface flaws are investigated. The concepts of crack closure are used in a fatigue growth analysis to account for constraint variation. The analysis, together with a traditional fatigue crack growth analysis which does not account for constraint variation, is used to predict flaw growth observed in experiments. Significant improvements in predicted fatigue life, as well as predicted crack shape, are obtained by accounting for the variation in constraint.

Fatigue Life Estimation of Welded Joints Including the Effects of Crack Closure Phenomena

2011 ◽  
Author(s):  
Diego Felipe Sarzosa Burgos ◽  
Claudio Ruggieri ◽  
Leonardo Barbosa Godefroid ◽  
Gustavo H. B. Donato
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Crack Opening ◽  
Weld Strength ◽  
Operating Life ◽  
Mechanical Heterogeneity

The integrity of mechanical components, particularly when they experience considerable fatigue damage during its operating life, can be strongly influenced by the presence of residual stress fields and mechanical heterogeneity. Premature closure of crack flanks greatly influences fatigue crack growth rate. Extensive elastic-plastic finite element analyses have been carried out to investigate detailed crack closure behavior in center cracked welded compact tension (CT) specimens with one level of weld strength mismatch. The finite element results show that homogeneous, soft material has higher crack opening loads than heterogeneous material with 50% overmatch conditions. Fracture testing conducted on C(T) specimens to measure fatigue crack growth rates for an ASTM A516 Gr. 70 steel weldment provide the experimental data to support such behavior. The fatigue life can be reduced by more than 100% for a condition of 50% overmatch when compared with the evenmatch condition. It was verified that most of time spent in fatigue propagation life is consumed at the beginning of the propagation life.

Hydrogen assisted fatigue life of Cr–Mo steel pressure vessel with coplanar cracks based on fatigue crack growth analysis

2020 ◽  
Vol 45 (38) ◽  
pp. 20132-20141
Author(s):  
Kai Ma ◽  
Jinyang Zheng ◽  
Zhengli Hua ◽  
Chaohua Gu ◽  
Ruiming Zhang ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Pressure Vessel ◽  
Growth Analysis ◽  
Coplanar Cracks

NUMERICAL SIMULATION ON FATIGUE CRACK GROWTH OF METAL SHEET INDUCED BY LASER SHOT PEENING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1646-1651 ◽  
Author(s):  
JIANFEI ZHAO ◽  
JIANZHONG ZHOU ◽  
SHU HUANG ◽  
SUQIN JIANG ◽  
YUJIE FAN
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Stress Field ◽  
Crack Growth ◽  
Shot Peening ◽  
Laser Shot ◽  
Finite Element Software

Based on theoretical analysis, finite element software ABAQUS and MSC.Fatigue were used to establish the forecasting model of fatigue life for laser shot peening (LSP) process. By using a standard stretch test sample of 6061-T6 aluminium alloy, the residual stress field induced by LSP was analyzed with ABAQUS code firstly, and then the stress field model was imported into MSC.Fatigue code for the crack growth analysis. The residual stress distribution and its effect on crack propagation life induced by LSP are numerical studied, and the fatigue life is predicted. The results show that numerical simulation approach is valuable for analyzing the fatigue crack growth and influence of process parameters on fatigue life.

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