Fatigue Growth Analysis of an Inclined Crack Under Uniaxial Cyclic Loading in Materials With Different Yield Strengths in Tension and Compression

1994 ◽  
Vol 116 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Xiangqiao Yan ◽  
Weisheng Lei
Keyword(s):  
Fatigue Crack ◽  
Cyclic Loading ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Strain Energy ◽  
Growth Analysis ◽  
Displacement Discontinuity ◽  
Inclined Crack ◽  
Tension And Compression

In the present paper, an improved strain-energy-density criterion presented recently for the commonly used fracture criterion, the minimum strain-energy-density criterion, is extended to the case of cyclic loading to predict mixed-mode fatigue crack growth in materials with different yield strengths in tension and compression. The analysis of the mixed-mode fatigue crack growth process is very complex. For the purpose of more precisely predicting the mixed mode fatigue crack growth process, we developed a numerical scheme in which the improved fatigue crack growth criterion is combined with the displacement discontinuity method, a boundary element method. In the fatigue crack growth analysis of an inclined crack under uniaxial cyclic loading, the stress intensity factors for each increment of the crack growth are calculated by means of the displacement discontinuity method. Fatigue growth analysis of an inclined crack under uniaxial cyclic loading in materials with different yield strengths in tension and compression is carried out.

Mixed-Mode Fatigue Crack Growth in Orthotropic Steel Decks

2006 ◽  
Vol 321-323 ◽  
pp. 733-738 ◽  
Author(s):  
Dong Ho Choi ◽  
Hang Yong Choi ◽  
Sang Hwan Chung ◽  
Hoon Yoo
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Strain Energy Density ◽  
Mixed Mode ◽  
Strain Energy ◽  
Density Factor ◽  
Energy Density Factor

The strain energy density factor approach under mixed-mode condition is used for the prediction of crack propagation in the orthotropic steel deck specimen, which is similar to that of existing suspension bridges. Stress intensity factor approach is used to compare with strain energy density factor approach for the fatigue crack growth analysis. The stress intensity factors are computed by numerical extrapolation using cracked models for the different crack length. The study shows that the fatigue crack propagation under mixed-mode condition is slower than that under mode I only. Parametric studies on the initial crack length, critical crack length and parameters related to crack growth equations are performed to show the influence of these parameters on the fatigue life.

Effect of Hydrogenated Water on Fatigue Crack Growth for Austenitic Stainless Steel in Simulated BWR Water Environment

2004 ◽  
Author(s):  
Li H. Wang
Keyword(s):  
Stainless Steel ◽  
Fatigue Crack ◽  
Cyclic Loading ◽  
Austenitic Stainless Steel ◽  
Fatigue Crack Growth ◽  
Water Chemistry ◽  
Crack Growth ◽  
Growth Stage ◽  
Transgranular Fracture ◽  
Cyclic Loading Condition

Fatigue crack growth rates (FCGR) of sensitized austenitic stainless steel (SS) were measured in simulated BWR water at 288 °C using compact tension specimens under different cyclic loading modes, including saw-tooth, trapezoidal and constant loading pattern. This study tested sensitized SS in normal water chemistry (NWC) and hydrogen water chemistry (HWC) respectively, and attempted to clarify the effect of low electrochemical corrosion potential on the FCGR of sensitized stainless steel. Significant environment effects on FCGR of sensitized stainless steel were observed in both water chemistries when compared with air fatigue curve. The pronounced suppression effect of HWC on crack growth in statically sustained load was not observed in cyclic loading condition. ASME curve doesn’t seem to be conservative and could not bound all the FCGR data tested in this study. In contrast, all of the measured FCGR data were bound by the JSME disposition curve. PLEDGE model proposed by General Electric reasonably predicted the FCGR of sensitized SS in NWC, but underestimated the FCGR in HWC. ANL’s superposition model successfully estimated the FCGR measured in both water chemistries. The fractography exhibited transgranular fracture mode during the crack initiation and growth stage. No differences in the appearance of fracture surface were observed in HWC and NWC. Only in very high DO environments, the sensitized 304 SS exhibited the mixed mode of intergranular and transgranular during growth stage.

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