Coalescence of Complex Cracks in Ex-Service Carbon Steel Pipe Bends During Burst Pressure Tests
Bibliographic record
Abstract
This paper presents burst pressure tests of two ex-service, 2 1/2-inch, SA-106 Grade B pipe bends with multiple part-through-wall axial cracks. The two pipes tested were sections of outlet feeders that were removed from the Point Lepreau Generating Station after 18.6 and 19.5 effective full-power years of service. The field of cracks was tightly distributed in the longitudinal and transverse directions of pipe bends on both inside surface and outside surfaces. The total length of the crack fields were 40 mm and 100 mm, respectively. The deepest crack was 73% through-wall. The burst pressure tests were performed at 90°C. The failure pressure was more than 4 times the design pressure. Post-test metallurgical examinations revealed mixed mode failures on the main fracture surface. The failure of the specimens was controlled by local plastic collapse of the ligaments of a small number of the deepest cracks in the field of cracks.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".