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.

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.

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.

50-Fold Difference in Region-II Fatigue Crack Propagation Resistance of Titanium Alloys: A Grain-Size Effect

1979 ◽  
Vol 101 (1) ◽  
pp. 86-90 ◽  
Author(s):  
G. R. Yoder ◽  
L. A. Cooley ◽  
T. W. Crooker
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Load Ratio ◽  
Plastic Zone Size ◽  
Crack Propagation Resistance ◽  
Order Of Magnitude ◽  
Region Ii

Fatigue crack growth rates (da/dN) in ambient laboratory air have been determined for a wide variety of materials from four basic α + β titanium alloy systems. Each material was cyclically loaded with a haversine waveform and a load ratio, R = 0.10. The results indicate that, at a constant value of stress-intensity range (ΔK), the width of the da/dN data band exceeds an order of magnitude. For example, at ΔK = 21 MPa·m1/2, a 50-fold difference in fatigue crack propagation rates is observed. Analysis of the crack growth rate data at this point indicates a systematic dependence on grain size (l), viz. that da/dN decreases with increasing l. An interpretation of this effect is offered in terms of reversed (cyclic) plastic zone size considerations.

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

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.

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