Study of fatigue crack propagation behaviour based on crack opening displacement distributions (noting the residual stress distribution near a notch)

1992 ◽  
Vol 14 (6) ◽  
pp. 421
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Stress Distribution ◽  
Crack Propagation ◽  
Crack Opening Displacement ◽  
Fatigue Crack Propagation ◽  
Crack Opening ◽  
Residual Stress Distribution ◽  
Opening Displacement

Heterogeneous Microstructure Effect on Residual Stress and Fatigue Crack Resistance in Dual-Phase Materials

2009 ◽  
Author(s):  
Masahito Mochizuki ◽  
Yoshiki Mikami
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Stress Distribution ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Compressive Residual Stress ◽  
Fatigue Tests ◽  
Residual Stress Distribution ◽  
Experimental Result ◽  
Microstructure Effect

The effect of transformation-induced microscopic residual stress on fatigue crack propagation behaviour of ferrite-martensite lamellar steel was discussed. Fatigue tests of prestrained and non-prestrained specimens were performed. Inflections and branches at ferrite-martensite boundaries were observed in the non-prestrained specimens. On the other hand, less inflections and branches were found in the prestrained specimens. The experimental results showed that the transformation induced microscopic residual stress has influence on the fatigue crack propagation behaviour. To estimate the microscopic residual stress distribution, a numerical simulation of microscopic residual stress induced by martensitic transformation was performed. The simulation showed that compressive residual stress was generated in martensite layer, and the result agree with the experimental result that inflections and branches were observed at ferrite-martensite boundaries. In addition, the change in the microscopic residual stress distribution by prestraining was also calculated to show the compressive residual stress changed to tensile by prestraining. This also agree with the experimental result of the observation of fatigue crack path.

Effects of Grain Size on Fatigue Crack Propagation in Copper Film

2010 ◽  
Vol 452-453 ◽  
pp. 289-292
Author(s):  
Kenichi Shimizu ◽  
Tashiyuki Torii
Keyword(s):  
Grain Size ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Crack Opening Displacement ◽  
Fatigue Crack Propagation ◽  
Fatigue Cracks ◽  
Crack Opening ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Opening Displacement

Using a fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover a circular through-hole in a base plate subjected to cyclic loads, annealed copper films of 100m thickness with different crystal grain sizes were fatigued. The fatigue crack propagation in the film with large grains was often decelerated, so the crack propagation rate of the film with the large grain was lower than that of the film with the small grain. When the crack propagation was decelerated, the crack opening displacement obtained from the film with large grain size was smaller than that obtained from the film with small grain size. The relationship between the fatigue crack propagation rate and the stress intensity factor estimated from the crack opening displacement was identical for the cracks in the film with the large grain and the small grain.

Sign in / Sign up

Export Citation Format

Share Document