Zh. Li et Kh. Schwalbe, Engineering treatment model for creep crack driving force estimation: CTODin terms of delta(5), ENG FRACT M, 68(2), 2001, pp. 221-233
Based on finite element analyses, a set of formulas for estimating the crac
k driving force under creep conditions in terms of the crack tip opening di
splacement (CTOD), delta (5), which measures the CTOD at the specimen side
surface, spanning the original crack tip over a gauge length of 5 mm, is pr
esented for three fracture specimens. These formulas are developed for stat
ionary and growing cracks for both plane stress and plane strain conditions
, validated for different creep laws and loading conditions. These formulas
are in closed form and accurately replicate finite element results. The cr
eep delta (5) is a promising load parameter For creep ductile materials. Th
e calculation of the creep delta (5) and the creep fracture analysis based
on the creep delta (5)-concept are very convenient. They can be done by use
of the nominal net section stress defined by the limit load of the cracked
body and the original uniaxial creep curve at the corresponding net sectio
n stress level. (C) 2000 Elsevier Science Ltd. All rights reserved.