Effect of Radial Offset Between Welded Back to Back Elbows on Their C2 Stress Index
Bibliographic record
Abstract
Pipe bends and elbows in process and power plant piping systems are sometimes added to provide additional flexibility along with their primary function of changing the direction of fluid flow. In special cases, piping systems may have double bends or elbows welded back to back with or without straight pipe in between. Due to manufacturing inaccuracies, back-to-back welded elbows may have a radial offset at the welded joint. Assessment of Class 1 piping following NB-3600 requires consideration of the C2 stress index of the girth butt weld, which is to be multiplied with the elbow C2 index. As an alternative, the C2 stress index may be calculated by finite element analysis using the maximum linearized membrane plus bending stress intensity. The effect of offset between the elbows at the welded joint on the elbow C2 stress indices is studied in this paper. Double elbows with elbow angles ranging from 30° to 90° and a radial offset of 1/32″ and 3/32″ at the weld are considered. Double elbows model with no weld in between and finite element model with single elbow are analyzed for comparison. The effect of angle between the bend planes of the two back-to-back elbows is studied. Results from the analyses are compared with C2 stress indices calculated as per NB-3680.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".