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- Title
Weibull stress model for cleavage fracture under high-rate loading.
- Authors
Gao, X.; Dodds Jr, R. H.; Tregoning, R. L.; Joyce, J. A.
- Abstract
This paper examines the effects of loading rate on the Weibull stress model for prediction of cleavage fracture in a low-strength, A515-70 pressure vessel steel. Interest focuses on low-to-moderate loading rates (KI < 2500 MPa √m s-1 ). Shallow cracked SE(B) specimens were tested at four different loading rates for comparison with previous quasi-static tests on shallow notch SE(B)s and standard C(T)s. To utilize these dynamic experimental data, we assume that the Weibull modulus (m) previously calibrated using quasi-static data remains invariant over the loading rates of interest. The effects of dynamic loading on the Weibull stress model enter through the rate-sensitive material flow properties, the scale parameter (σu ) and the threshold Weibull stress (σw-min ). Rate-sensitive flow properties are modelled using a viscoplastic constitutive model with uniaxial, tension stress–plastic strain curves specified at varying plastic strain rates. The analyses examine dependencies of σw-min and σu on KI . Present results indicate that σw-min and σu are weak functions of loading rate KI for this pressure vessel steel. However, the predicted cumulative probability for cleavage exhibits a strong sensitivity to σu and, consequently, the dependency of σu on KI is sufficient to preclude use of the static σu value for high loading rates.
- Subjects
CRACKING of pressure vessels; METAL fractures; WEIBULL distribution
- Publication
Fatigue & Fracture of Engineering Materials & Structures, 2001, Vol 24, Issue 8, p551
- ISSN
8756-758X
- Publication type
Article
- DOI
10.1046/j.1460-2695.2001.00421.x