Uncertainty Quantification and Comparison of Weld Residual Stress Measurements and Predictions.

Technical Report · Sat Oct 01 04:00:00 EDT 2016

DOI:https://doi.org/10.2172/1330928· OSTI ID:1330928

Lewis, John R. ^[1]; Brooks, Dusty Marie ^[1]

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1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

In pressurized water reactors, the prevention, detection, and repair of cracks within dissimilar metal welds is essential to ensure proper plant functionality and safety. Weld residual stresses, which are difficult to model and cannot be directly measured, contribute to the formation and growth of cracks due to primary water stress corrosion cracking. Additionally, the uncertainty in weld residual stress measurements and modeling predictions is not well understood, further complicating the prediction of crack evolution. The purpose of this document is to develop methodology to quantify the uncertainty associated with weld residual stress that can be applied to modeling predictions and experimental measurements. Ultimately, the results can be used to assess the current state of uncertainty and to build confidence in both modeling and experimental procedures. The methodology consists of statistically modeling the variation in the weld residual stress profiles using functional data analysis techniques. Uncertainty is quantified using statistical bounds (e.g. confidence and tolerance bounds) constructed with a semi-parametric bootstrap procedure. Such bounds describe the range in which quantities of interest, such as means, are expected to lie as evidenced by the data. The methodology is extended to provide direct comparisons between experimental measurements and modeling predictions by constructing statistical confidence bounds for the average difference between the two quantities. The statistical bounds on the average difference can be used to assess the level of agreement between measurements and predictions. The methodology is applied to experimental measurements of residual stress obtained using two strain relief measurement methods and predictions from seven finite element models developed by different organizations during a round robin study.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1330928
• Report Number(s): SAND2016-10932; 648709
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
42 ENGINEERING
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CRACK PROPAGATION
CRACKS
DATA ANALYSIS
DATA COVARIANCES
FINITE ELEMENT METHOD
FORECASTING
LIMITING VALUES
MEASURING METHODS
RESIDUAL STRESSES
STATISTICS
STRESS CORROSION
TOLERANCE
VARIATIONS
WATER
WELDED JOINTS