TY - JOUR
T1 - ESTIMATION METHOD OF CREEP CRACK INITIATION AND THE EFFECT OF NOTCH SHAPE AND SPECIMEN WIDTH OF CREEP CRACK INITIATION AND PROPAGATION.
AU - Yokobori, Tosimitsu
AU - Kuriyama, Takashi
AU - Yokobori, Takeo
AU - Kako, Takuzou
PY - 1986/5
Y1 - 1986/5
N2 - 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.
AB - 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.
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M3 - Article
AN - SCOPUS:0022722548
SN - 0387-5008
VL - 52
SP - 1221
EP - 1227
JO - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
JF - Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
IS - 477
ER -