Comparison of finite element and influence function methods for three-dimensional elastic analysis of boiling water reactor feedwater nozzle cracks
The paper compares the finite element (FE) and influence function (IF) methods for a three-dimensional elastic analysis of postulated circular-shaped surface cracks in the feedwater nozzle of a typical boiling water reactor (BWR). The FE method is incorporated in a direct manner. The nozzle and crack geometry and the complex loading are all included in the model which simulates the structural crack problem. The IF method is used to compute stress intensity factors only when the uncracked stress field (that is, the stress in the uncracked solid at the locus of the crack to be eventually considered) has been computed previously. The IF method evaluates correctly the disturbance of this uncracked stress field caused by the crack by utilizing a method of elastic superposition. Both the IF and FE methods are described in detail in the paper and are applied to several test cases chosen for their similarity to the nozzle crack problem and for the availability of an accurate published result obtained from some recognized third method of solution. Results are given which summarize both the accuracy and the direct computer costs of the two methods.
- Research Organization:
- Failure Analysis Associates, Palo Alto, CA (USA); Teledyne Materials Research Co., Waltham, MA (USA)
- OSTI ID:
- 7331317
- Report Number(s):
- EPRI-NP-261; TRN: 77-006164
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BWR TYPE REACTORS
PRESSURE VESSELS
NOZZLES
STRESS ANALYSIS
ACCURACY
COMPARATIVE EVALUATIONS
COST
CRACKS
FINITE ELEMENT METHOD
REACTOR COOLING SYSTEMS
THREE-DIMENSIONAL CALCULATIONS
CONTAINERS
COOLING SYSTEMS
NUMERICAL SOLUTION
REACTOR COMPONENTS
REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled