Constraint effects on fracture initiation loads in HSST wide-plate tests
- Illinois Univ., Urbana, IL (United States)
During the period 1984--1987, researchers of the Heavy-Section Steel Technology program at the Oak Ridge National Laboratory performed a unique series of fracture mechanics tests using exceptionally large, SE(T) specimens (a/W=0.2) fabricated from a reactor pressure vessel material, A533B Class 1 steel. This study re-examines fracture initiation loads in the wide-plate tests using two constraint assessment methodologies developed over the past five years: the J-Q toughness locus approach and the toughness scaling approach based on a local failure criterion for cleavage. Both approaches demonstrate a significant loss of constraint in the elastic-plastic fields ahead of the crack in the wide-plate specimens caused by the inherent negative T-stress of the shallow notch SE(T) configuration. Moreover, the 25mm wide machined notch required for specimen fabrication is shown to further reduce constraint by introducing a traction free surface very near the crack tip. Both of these factors combined to reduce near-tip stresses by 10% below those of the small-scale yielding, SSY (T=O), fields. This reduction places fracture results for the wide-plate specimens within the J-Q toughness locus defined by fracture toughness tests on the A533B material and within the constraint corrected J{sub c} values defined by the toughness scaling methodology.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Illinois Univ., Urbana, IL (United States); Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10106607
- Report Number(s):
- NUREG/CR--6259; UILU-ENG--94-2009; ORNL/TM--12796; ON: TI95005273
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220200
36 MATERIALS SCIENCE
360103
CLEAVAGE
COMPONENTS AND ACCESSORIES
CRACK PROPAGATION
CRACKS
ELASTICITY
FINITE ELEMENT METHOD
FRACTURE MECHANICS
IMPACTS
LOADING
MECHANICAL PROPERTIES
NUCLEAR POWER PLANTS
PLASTICITY
PLATES
PRESSURE VESSELS
REACTOR MATERIALS
STEEL-ASTM-A533-B
STRESSES
TENSILE PROPERTIES
TESTING