Simulations of Ductile Fracture in Pipeline Steels Under Quasi-Static and Dynamic Loading Conditions
Bibliographic record
Abstract
To circumvent numerous costly experimental investigations of full scale pipeline burst tests, fracture resistance parameters are determined from small scale lab tests for a given material.Developed over the past several decades, fracture parameters such as the Charpy V-notch energy, drop weight tear test (DWTT) absorbed energy, and most recently the crack tip opening angle (CTOA) have proven to be useful design tools for the pipeline industry.The CTOA is becoming a rival measure of ductile fracture propagation; however, there are several aspects such as the effect of loading mode and loading rate, which are still under investigation.In this thesis, extensive finite element simulations of ductile fracture propagation were analyzed using the cohesive zone model (CZM).The analyses focused on the effect of loading mode under quasi-static loading conditions on the CTOA, and higher loading rates on the CTOA and CZM parameters.Two common pipeline steels were used in this work, namely, American Petroleum Institute (API) standard C2-X70 and C4-X100.A small scale yielding (SSY) model, a clamped single edge notch tensile (SENT) model, and a DWTT model were examined under quasi-static loading conditions.The SSY model 4.2 Analysis Methodology ..............
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".