Crack shape evolution of surface flaws under fatigue loading of austenitic pipes

1997 ◽  
Vol 174 (1) ◽  
pp. 17-24 ◽  
Author(s):  
J.H Kim ◽  
I.S Hwang
Author(s):  
Olga Samsonova ◽  
◽  
Mikhail Nikhamkin ◽  
Ivan Konev ◽  
◽  
...  

Author(s):  
Yosuke Anai ◽  
Toshio Niwa ◽  
Koji Gotoh

Fatigue life estimation for planar cracks, e.g. part-through surface cracks or embedded cracks is very important because most of fatigue cracks found in welded built-up structures show planar crack morphologies. Although authors had proposed the estimation procedure of crack shape evolution for a planar crack based on the fracture mechanics approach, this method cannot apply if the values of stress intensity factor at the vertices of the surface crack approximated as an ellipse cannot calculated. Then, development of the shape evolution procedure of a planer crack under the stress field with arbitrary gradient, because fatigue cracks in welded built-up structures exist near the stress concentrated region. A Practical estimation formula the shape evolution of a surface crack under stress field with the gradient is proposed in this study. This formula is established by considering the stress field under no crack condition and some former proposed formulae under uniform and pure bending stress fields. The validity of the proposed formula are confirmed by comparing some measured surface crack shape evolutions under some stress gradient conditions.


Author(s):  
Koji Gotoh ◽  
Keisuke Harada ◽  
Yosuke Anai

Fatigue life estimation for planar cracks, e.g. part-through surface cracks or embedded cracks is very important because most of fatigue cracks found in welded built-up structures show planar crack morphologies. Fatigue crack growth behaviour of an embedded crack in welded joints is investigated in this study. The estimation procedure of crack shape evolution for an embedded crack is introduced and validation of the estimation procedure of fatigue crack growth based on the numerical simulation of fatigue crack growth with EDS concept for an embedded crack is performed. The validity of the proposed shape evolution estimation method and the fatigue crack growth simulation based on the fracture mechanics approach with EDS concept are confirmed.


1983 ◽  
Vol 105 (3) ◽  
pp. 215-218 ◽  
Author(s):  
M. Jolles

The effects of the variation of stress field triaxiality on the prediction of the fatigue growth of semielliptic surface flaws are investigated. The concepts of crack closure are used in a fatigue growth analysis to account for constraint variation. The analysis, together with a traditional fatigue crack growth analysis which does not account for constraint variation, is used to predict flaw growth observed in experiments. Significant improvements in predicted fatigue life, as well as predicted crack shape, are obtained by accounting for the variation in constraint.


1991 ◽  
Vol 24 (6) ◽  
pp. 291-302 ◽  
Author(s):  
C.N. Ma ◽  
J.C.P. Kam

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