Development of models for warm prestressing
The objective of this project is to evaluate available mathematical models and associated fracture criteria for predicting warm prestress (WPS) effects. A verified model of the WPS phenomenon is required before credit for improved low temperature toughness can be taken in analysis of postulated accident scenarios such as pressurized thermal shock. The primary basis of evaluation is finite-element analysis using a highly refined mesh and work hardening, modeled by a piece-wise linear fit of stress-strain data. The criteria being evaluated are J/sub e/ (Chell, et al.), critical stress (Curry), T*/sub p/ (Atluri) and a criterion introduced herein which is related to differential CTOD and denoted dCTOD*FLOW. The finite element model is used to simulate a load-unload-cool-fracture (LUCF) type of WPS cycle for which experimental results are available. The various models and criteria are evaluated in terms of their agreement with the finite-element results such as crack opening displacements, stresses and plastic-zone sizes, and in terms of their ability to predict fracture load. The nonfinite-element-based models of Chell and Curry are used to simulate 32 additional WPS experiments so as to further assess the relative merits of the models and the J/sub e/, critical stress, and dCTOD*FLOW fracture criteria. While K/sub Ic/ scatter band behavior allows significant latitude for manipulation of model predictions, which impedes critical evaluation of the models and criteria, both models and all three fracture criteria are found to predict WPS behavior which is qualitatively consistent with experimental data.
- Research Organization:
- Computational Mechanics, Julian, PA (USA); PROSIG, Inc., Tulsa, OK (USA); Materials Engineering Associates, Inc., Lanham, MD (USA); Nuclear Regulatory Commission, Washington, DC (USA). Div. of Engineering Safety
- OSTI ID:
- 6574035
- Report Number(s):
- NUREG/CR-4491; MEA-2122; ON: TI87900475; TRN: 87-019445
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
22 GENERAL STUDIES OF NUCLEAR REACTORS
CRACK PROPAGATION
MATHEMATICAL MODELS
FRACTURE MECHANICS
COMPARATIVE EVALUATIONS
STEEL-ASTM-A533-B
MATERIALS TESTING
CRACKS
ELASTICITY
EVALUATION
EXPERIMENTAL DATA
FEASIBILITY STUDIES
FINITE ELEMENT METHOD
FLOW STRESS
FRACTURE PROPERTIES
FRACTURES
INTEGRALS
LOSS OF COOLANT
MECHANICAL PROPERTIES
MESH GENERATION
PLASTICITY
POISSON RATIO
PREDICTION EQUATIONS
STRAIN HARDENING
STRESS ANALYSIS
STRESS INTENSITY FACTORS
THERMAL SHOCK
TRANSITION TEMPERATURE
YOUNG MODULUS
ACCIDENTS
ALLOYS
CARBON STEELS
DATA
EQUATIONS
FAILURES
HARDENING
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
MECHANICS
NUMERICAL DATA
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
REACTOR ACCIDENTS
STEELS
STRESSES
TENSILE PROPERTIES
TESTING
THERMODYNAMIC PROPERTIES
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360103 - Metals & Alloys- Mechanical Properties
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