scholarly journals Improvement of a Cycle J Integral for CT-Specimens

1985 ◽  
Author(s):  
Liu Shao-Lun ◽  
Xie Ji-Zhou
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Integral Formula ◽  
J Integral ◽  
Application Range

The cycle J integral formula for CT-specimens has been improved as follows Δ J = 2 B b a 1 • U + a 2 • Δ δ + 2 B b U e { -1.2025 a w + 0.6233 0.3 ⩽ a w ⩽ 0.53 -0.02 Sin ⁡ π 0.23 a w - 0.53 0.53 < a w < 0.95 This formula is applicable to the fatigue crack propagation range of 0.3 ≤a/w<0.95. In comparision with other formulae of cycle J integral, the application range of the above expression is enlarged and its precision is also increased to a certain extent.

Improvement of a Cycle J Integral for CT Specimens

1986 ◽  
Vol 108 (3) ◽  
pp. 521-524 ◽  
Author(s):  
Shao-Lun Liu ◽  
Ji-Zhou Xie
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Integral Formula ◽  
J Integral ◽  
Application Range

The cycle J integral formula for CT specimens has been improved as follows: ΔJ=(2/Bb)(α1•U + α2•ΔP•Δδ) + (2/Bb)Ue−1.2025a/w + 0.6233 for 0.3≤a/w≤0.53; ΔJ=(2/Bb)(α1•U + α2•ΔP•Δδ) + (2/Bb)Ue−0.02 sin[(π/0.23)(a/w−0.53)] for 0.53<a/w<0.95. This formula is applicable to the fatigue crack propagation range of 0.3≤a/w<0.95. In comparison with other formulae of the cycle J integral, the application range of the above expression is enlarged and its accuracy is also increased to a certain extent.

Application of J-Integral to High-Temperature Crack Propagation: Part II—Fatigue Crack Propagation

1979 ◽  
Vol 101 (2) ◽  
pp. 162-167 ◽  
Author(s):  
Shuji Taira ◽  
Ryuichi Ohtani ◽  
Tomio Komatsu
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Large Scale ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Integral Approach ◽  
Fatigue Crack Propagation Rate ◽  
J Integral ◽  
Creep Crack

On the basis of the successful results of our previous study on a J-integral approach to the creep crack propagation of steels, the applicability of the creep J-integral to the time dependent fatigue crack propagation in creep range was studied. A satisfactory correlation was obtained between crack propagation rate and creep J-integral, and the same correlation was found in creep crack propagation under constant load as well as two-step loading. It was also found that the cycle dependent fatigue crack propagation rate could be successfully correlated by the cyclic J-integral. The high crack propagation rate in large scale yielding fatigue may be in agreement with the straight line extrapolation on log-log plots of the linear elastic fatigue crack propagation rate versus cyclic J-integral data.

scholarly journals J-Integral Approach to Fatigue Crack Propagation in Vulcanized Natural Rubber

2003 ◽  
Vol 69 (680) ◽  
pp. 758-765
Author(s):  
Keisuke TANAKA ◽  
Yoshiaki AKINIWA ◽  
Hirohisa KIMACHI ◽  
Kazuyuki ITOH
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Natural Rubber ◽  
Fatigue Crack Propagation ◽  
Integral Approach ◽  
J Integral

scholarly journals Elasto-Plastic Fracture Mechanics Analysis of the Effect of Shot Peening on 300M Steel

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3538
Author(s):  
Shuai Hou ◽  
Zhihai Cai ◽  
Youli Zhu ◽  
Qizhi Zhao ◽  
Yong Chen ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Residual Strain ◽  
Shot Peening ◽  
Crack Depth ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
J Integral ◽  
Stress Layer

A modified J-integral calculation method is adopted to fix the problem of the quantitative evaluation of the crack propagation of shot-peened structures. Considering the residual stress, residual strain, and residual strain energy, the effect of shot peening on the J-integral parameters of semi-elliptic surface crack fronts is quantitatively calculated and a method is provided for the performance evaluation of the shot peening layer. First, the shot peening process is simulated, then the fatigue crack is generated by changing the constraint condition and a far-field load is applied to calculate the J-integral parameters, crack propagation rate, and crack kinking angle. The effects of different crack depths and shot velocities on the fracture parameters are analyzed. The results show that the reduction in the J-integral value after shot peening decreases with the increase in the crack depth when the shot velocity is a certain value, which indicates that shot peening is more beneficial for suppressing the fatigue crack propagation. When the crack depth is greater than the depth of the compressive stress layer, shot peening accelerates the crack propagation. The reduction in the J-integral value decreases with the increase in shot velocity when the crack depth is a certain value; therefore, increasing shot velocity is more beneficial for retarding fatigue crack propagation.

Fatigue crack propagation in aluminum plates with composite patch including plasticity effect

2017 ◽  
Vol 232 (11) ◽  
pp. 2122-2131 ◽  
Author(s):  
A Albedah ◽  
Sohail MA Khan ◽  
B Bachir Bouiadjra ◽  
F Benyahia
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Load Ratio ◽  
J Integral ◽  
Electron Microscopic ◽  
Composite Patch ◽  
Aa 2024 ◽  
Aluminum Plates

In this paper, we analyzed experimentally and numerically the behavior of fatigue crack in aluminum plates repaired with bonded composite patch. We studied the behavior of repaired crack in AA 2024 T3 and AA 7075 T6 under two levels of applied fatigue stresses: maximal stresses of 70 and 120 MPa at a load ratio of 0.1. In the experimental part, the fatigue life of unrepaired and repaired notched specimens were determined. In the numerical part, the J integral around repaired and unrepaired crack tips was calculated. The numerical and the experimental results were used to plot the crack velocity (da/dN) as a function of the J integral. The analysis was completed with scanning electron microscopic observations on fracture surfaces of repaired and unrepaired specimens. It was found that patch improves the fatigue life but this improvement is considerably reduced with the increase in the applied fatigue load. The Al 2024 T3 presents better resistance to fatigue crack propagation in both repaired and unrepaired cases.

Development of Flaw Evaluation System for Creep-Fatigue Crack Propagation of High-Temperature

2004 ◽  
Vol 261-263 ◽  
pp. 1307-1312
Author(s):  
K. Fujishita ◽  
Noriko Miura ◽  
Y. Takahashi ◽  
Yukihiro Nakayama
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Evaluation System ◽  
Central Research ◽  
J Integral ◽  
Creep Fatigue ◽  
Integral Range ◽  
Creep Fatigue Crack

Central Research Institute of Electric Power Industry (CRIEPI) has been conducting a research project on the verification of evaluation method for structural integrity of high-temperature components. As a part of the framework, we developed a flaw evaluation system on PC to predict creep-fatigue crack propagation, which was considered to be an essential crack driving force at high temperature especially in case where stresses caused by thermal loading were significant. The system is featured by easy and dialogical operation with graphical user interface. Fatigue and creep crack propagation behavior can be predicted using fatigue J-integral range and creep J-integral, respectively, which are the variations of the non-linear fracture mechanics parameter, J-integral. Both fatigue J-integral range and creep J-integral are calculated by the reference stress method with revised solutions developed by detailed finite element analysis.

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