SYMPOSIA PAPER Published: 01 January 2000

Determination of -Parameter Considering Effects of Accumulated Creep Deformation During Loading Period


Most of the assessment equations for Ct, which is a well-known fracture parameter characterizing creep and creep-fatigue crack growth rates, have limited applicability to constant load conditions. However, crack growth due to creep can also occur under varying load conditions when the load rate is slow enough such that accumulated creep deformation near the crack tip can't be neglected. An estimation equation of the Ct-parameter that can be applied to the case of slow load rising was derived by the authors and denoted as (Ct)r.

In this paper, correlation between (Ct)r at the end of the load-rising period and Ct at the beginning of the succeeding load hold period is shown. And a new Ct estimation equation that can be applied to the load hold period following a slow load rising period is derived using the relation between (Ct)r and Ct. Finite element analyses of several cases with various load-rising conditions were performed. The results support accuracy of the proposed Ct estimation scheme. General applicability of the equation is also discussed.

Author Information

Lee, JH
Sungkyunkwan University, Suwon, Korea
Kim, YJ
Sungkyunkwan University, Suwon, Korea
Yoon, KB
Chung Ang University, Seoul, Korea
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Developed by Committee: E08
Pages: 313–326
DOI: 10.1520/STP13411S
ISBN-EB: 978-0-8031-5418-6
ISBN-13: 978-0-8031-2617-6