In this paper, the authors show that creep crack propagation life is controlled by the size of the micro cracking region formed before crack initiation. Since, for a circular notch the stress concentration factor is small compared with that for a V type sharp notch, the size of the micro cracking region is much larger than that for a V type sharp notch. So the creep crack propagation life becomes very short. These micro cracking regions are formed due to concentrated plastic deformation. But the relative notch opening displacement RNOD//c equals DELTA phi //i/ phi //0( DELTA phi //i equals phi //i minus phi //0, phi //i is the notch opening displacement at the crack initiation, phi //0: Initial notch opening displacement) is the best accurate parameter of crack initiation, independent of such different creep crack propagation characteristics.
|Number of pages||7|
|Journal||Nippon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A|
|Publication status||Published - 1986 May|
ASJC Scopus subject areas
- Mechanical Engineering