Elastic fracture mechanics analysis of thick-walled curved tubing with a semi-elliptical surface crack by the boundary element method
Bibliographic record
Abstract
In this paper, the boundary element method is used to obtain the mode I stress intensity factors (SIFs) for a semi-elliptical crack in thick-walled curved tubing or elbow under internal pressure. A relatively wide range of geometric parameters for the tubing – the bend radius ratio, the cross-sectional radius ratio, and the angular extent of the circular bend – is considered. For each case of the curved tube geometry, a crack of semi-minor to semi-major axis ratio of 0.8, with depth varying from 20 per cent to 80 per cent of the wall thickness at the intrados is analysed. The computed values of the normalized SIFs are shown to be higher than those corresponding to a straight cylinder for the same relative crack depth and cross-sectional radius ratio. They are also found not to vary significantly along much of the crack periphery in the cases considered, increasing rapidly only as the free surface is approached. Furthermore, for a given relative crack size and location, they increase with decreasing bend radius ratio and decreasing cross-sectional radius ratio, but are, however, less sensitive to the angular extent of the elbow.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".