Prediction of Fatigue Threshold of Notched Components

1984 ◽  
Vol 106 (2) ◽  
pp. 192-199 ◽  
Author(s):  
K. Tanaka ◽  
Y. Nakai
Keyword(s):  
Experimental Data ◽  
Stress Intensity ◽  
Low Carbon Steel ◽  
Fatigue Threshold ◽  
Low Carbon ◽  
Stress Intensity Range ◽  
Intensity Range ◽  
Effective Stress Intensity Range ◽  
Consistent Method ◽  
Tip Radius

A consistent method is proposed to predict significant properties concerning the notch fatigue threshold from three experimental data: the fatigue limit of smooth specimens, the threshold stress intensity range for a long crack, and the effective stress intensity range at the threshold for a long crack. Based on the model of the intrinsic crack combined with crack closure, the fatigue limits for crack initiation and fracture from a notch, the length of a nonpropagating crack, and the notch tip radius at the branch point are all derived in a consistent way. The predicted results are compared with the experimental data of a low-carbon steel, and good agreement is obtained.

scholarly journals Fatigue threshold and closure in duplex low carbon steel.

1988 ◽  
Vol 37 (420) ◽  
pp. 1077-1083 ◽  
Author(s):  
Keiji OGURA ◽  
Yoshio MIYOSHI ◽  
Izuru NISHIKAWA ◽  
Yasutaka NAKAO
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Fatigue Threshold ◽  
Low Carbon

Mechanisms and Mechanics of Fatigue Crack Propagation in Zr-Based Bulk Metallic Glass

2008 ◽  
Vol 378-379 ◽  
pp. 317-328 ◽  
Author(s):  
Yoshikazu Nakai ◽  
Makoto Seki
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Metallic Glass ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Loading Frequency ◽  
Stress Intensity Range ◽  
Intensity Range

In the present study, the fatigue crack propagation tests of Zr-based metallic glass were conducted in laboratory air, and the fracture surface was observed to clarify the effects of loading frequency and the stress ratio. In spite of being brittle material, the metallic glass showed stable fatigue crack propagation behaviour, and the relationship between the crack propagation rate, da/dN, and the stress intensity range, K, can be divided into three regions as well as conventional crystalline metals. The crack propagation rate can be expressed as a function of the stress intensity range by Paris law in the middle region. The power in Paris law was 1.4, and it is considerably smaller than the value for conventional crystalline metals. The threshold stress intensity range, Kth, was 1.8 MPam1/2. The effects of the stress ratio and the loading frequency were not observed on the relationships, da/dN-K and da/dN-Keff. Then, the fatigue crack propagation of the metallic glass is cycle dependent in laboratory air.

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