Application of Plastic Strain Damage Models to Characterize Dent with Crack
Bibliographic record
Abstract
Abstract Currently, the allowable strain limit for a plain dent is 6 percent as per ASME* B31.81 for gas pipelines. Field experience has shown that the 6% strain limit for plain dents could be overly conservative, which can result in unnecessary excavations and repairs. Recently, efforts to develop an alternative strain limit have been proposed. In this paper, two plastic damage-based models, namely, ductile failure damage and strain limit damage, and one minimum elongation-based criterion are reviewed. Attempts have been made to use these models to characterize rock dents associated with cracks in terms of a plastic damage severity factor and its susceptibility to crack initiation. Field excavations and finite element analysis are utilized to validate these models using two real pipeline dents from two different pipeline operators, operating in USA and Canada. The results have shown that the internal cracks were formed at the time of the initial indentation and can be predicted by the plastic strain damage based ductile failure models. On the basis of this, a newly developed approach that combines in-line inspection (ILI) technologies (caliper and magnetic flux leakage [MFL]) is introduced and utilized to discriminate between dent with corrosion and dent with crack, and identify critical dents in the pipelines.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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".