Fatigue crack propagation rate model based on a dislocation mechanism

1986 ◽  
Vol 5 (10) ◽  
pp. 972-974 ◽  
Author(s):  
P. K. Mazumdar ◽  
S. Jeelani
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Rate Model ◽  
Dislocation Mechanism ◽  
Model Based

Effect of Constraint on Fatigue Crack Propagation in Notched Plates

2010 ◽  
Author(s):  
Xin Wang
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Rate Model ◽  
Propagation Law ◽  
Crack Tip Constraint

It has been observed that the loss of crack tip constraint leads to enhanced resistance to both cleavage and ductile tearing. Recent developments on constraint-based fracture mechanics have enabled the practical assessment of defective components including the constraint effect. In fatigue analyses, it is common practice to use the Paris crack propagation law, which is based on the stress intensity factor alone. Although in recent years several research attempts have been made to investigate the effect of constraint on fatigue, how to quantify the effect of crack tip constraint on the fatigue crack propagation rate is still an open issue. In this paper, the effect of crack tip constraint on the fatigue crack propagation of small cracks at notched plates is investigated. A fatigue crack propagation rate model developed earlier which incorporates both low and high constraint conditions is used. It is shown that the effect of constraint on crack propagation rate is significant when the crack is small (within the stress concentration of the notches). This effect can be accounted for by using the fatigue crack propagation rate model.

Effect of Constraint on Fatigue Crack Propagation in T-Plate Welded Joints

2007 ◽  
Author(s):  
Xin Wang ◽  
Qing Gao
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Welded Joints ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Fatigue Crack Propagation Rate ◽  
Rate Model ◽  
Crack Tip Constraint

It has been observed that the loss of crack tip constraint leads to enhanced resistance to both cleavage and ductile tearing. Recent developments on constraint-based fracture mechanics have enabled the practical assessment of defective components including the constraint effect. However, how to quantify the effect of crack tip constraint on the fatigue crack propagation rate is still an open issue. It is common practice to use the Paris crack propagation law, which is based on the stress intensity factor alone. In this paper, the effect of crack tip constraint on the fatigue crack propagation of small cracks at T-plate welded joints is investigated. A fatigue crack propagation rate model is developed incorporating both low and high constraint conditions. It is shown that the effect of constraint on crack propagation rate is significant when the crack is small (within the stress concentration of the weld joints). This effect can be accounted for by using the proposed fatigue crack propagation rate model.

Test Stand for Analysis of Fatigue Crack Propagation under Bending with Torsion

2008 ◽  
Vol 144 ◽  
pp. 90-93 ◽  
Author(s):  
Grzegorz Gasiak ◽  
Grzegorz Robak
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Digital Camera ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Test Stand ◽  
Crack Development ◽  
Fatigue Crack Propagation Rate ◽  
Fatigue Crack Development

The paper presents a test stand for measurements of fatigue crack propagation. The stand includes a fatigue machine MZGS–100 and a device for registration of the crack length. The test stand is equipped with a stereoscopic microscope with fluent magnification of 7× – 67.5×. The microscope can be applied for observation of fatigue crack development. The microscope is also equipped with a digital camera, which enables continuous observation of fatigue crack development on the computer monitor and it is not necessary to stop the machine. The test results obtained at this stand can be used for determination of fatigue life and fatigue crack propagation rate.

Sign in / Sign up

Export Citation Format

Share Document