Application of a Simplified Constant Crack Tip Opening Angle Model to Crack Propagation Analyses in Steel Pipelines
Bibliographic record
Abstract
Abstract In this paper, a simplified constant crack tip opening angle (CTOA) model is presented and used to analyze two different pipeline steels. The steels examined in this work were an American Petroleum Institute (API) Standard X65 steel and a Japanese Industrial Standard (JIS) steel with the grade designation of STPG370. The commercial finite element (FE) code ABAQUS 2017x was used to generate the models and solve the analyses. The proposed propagation model was first verified through comparing the numerical results with published data. The steady-state fracture velocity data from the simplified model matched the data from literature within a maximum difference of 2% while drastically reducing the computational time required by an order of magnitude. Following the verification of the simplified model, it was then used to analyze recent experimental data. The model was able to match the experimental crack velocity data within a difference of 4%.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".