Plane strain crack growth models for fatigue crack growth life predictions

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:191342

Bloom, J M ^[1]; Daniewicz, S R ^[2]; Hechmer, J L ^[3]

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1. Babcock and Wilcox, Alliance, OH (United States). Research and Development Div.
2. Mississippi State Univ., Mississippi State, MS (United States)
3. Babcock and Wilcox, Barberton, OH (United States). Nuclear Equipment Div.

This paper discusses the development of a crack closure expression for the 4-point bend specimen using numerical results obtained from a modified strip-yield model. Data from tests of eight 4-point bend specimens were used to estimate the specimen constraint factor (stress triaxiality effect). The constraint factor was then used in the estimation of the crack opening stresses for each of the bend tests. The numerically estimated crack opening stresses were used to develop an effective stress intensity factor range, {Delta}K{sub eff}. The resulting crack growth rate data when plotted versus {Delta}K{sub eff} resulted in a material fatigue crack growth rate property curve independent of test specimen type, stress level, and R-ratio. Fatigue crack growth rate data from center cracked panels using Newman`s crack closure model, from compact specimens using Eason`s R-ratio expression, and from bend specimens using the model discussed in this paper are all shown to fall along the same straight line (on log-log paper) when plotted versus {Delta}K{sub eff} even though crack closure differs for each specimen type.

• OSTI ID: 191342
• Report Number(s): CONF-950740--; ISBN 0-7918-1337-1
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
CRACK PROPAGATION
FATIGUE
MATHEMATICAL MODELS
PROBABILISTIC ESTIMATION
REACTOR MATERIALS
SERVICE LIFE
STANDARDS
STEELS
STRESS INTENSITY FACTORS
WATER COOLED REACTORS