The correlation between grain size and plastic zone size for environmental hydrogen assisted fatigue crack propagation

1975 ◽  
Vol 9 (10) ◽  
pp. 1089-1094 ◽  
Author(s):  
J.D. Frandsen ◽  
H.L. Marcus
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Plastic Zone ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Plastic Zone Size ◽  
Zone Size

Analytical Prediction Model for Fatigue Crack Propagation Rate under Tension-Compression Loading

2013 ◽  
Vol 842 ◽  
pp. 455-461
Author(s):  
Yu Sha ◽  
Shi Gang Bai ◽  
Ya Hui Wang
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Plastic Zone ◽  
Crack Propagation ◽  
Compressive Stress ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Zone Size ◽  
Compression Loading

Elastic–plastic finite element analyses have been performed to study the compressive stress effect on fatigue crack growth under applied tension–compression loading. The near crack tip stress, crack tip opening displacement and crack tip plastic zone size were obtained for a kinematic hardening material. The results have shown that the near crack tip local stress, displacement and reverse plastic zone size are controlled by the maximum stress intensity factors Kmax and the applied compressive stress σmaxcom under tension–compression. Based on the finite element analysis results, a fatigue crack propagation model using Kmax and σmaxcom as a parameters under tension–compression loading has been developed.The models under tension–compression loading agreed well with experimental observations.

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.

Fatigue Crack Propagation Rates for Duralumin in Simple Bending

1975 ◽  
Vol 97 (2) ◽  
pp. 179-186 ◽  
Author(s):  
P. J. Cain ◽  
R. Plunkett ◽  
T. E. Hutchinson
Keyword(s):  
Stress Intensity Factor ◽  
Grain Size ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Plastic Zone ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Fourth Power ◽  
Simple Tension

Flat sheet stock of 2024-T3 Duralumin was tested for fatigue crack propagation in simple bending. Transcrystalline cracking was observed at a rate proportional to stress intensity factor squared at low levels where the plastic zone is less than grain size. A mixture of trans-and-intercrystalline cracking was observed at a rate proportional to stress intensity factor to the fourth power at high levels where the plastic zone is larger than grain size. A strain redistribution mechanism giving constant stress intensity factor through the thickness is postulated. The combination of strain redistribution in bending and change of mechanism with plastic zone size leads to a macroscopic behavior which is different from that previously reported for simple tension, particularly in mild steel.

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