Evaluation of Fracture Toughness Test Methods for Linepipe Steels2This licence is granted on the condition that clear attribution is given to the author(s) and Natural Resources Canada and, when feasible, that the Crown copyright is acknowledged as follows: © Her Majesty the Queen in Right of Canada, as represented by the Minister of Natural Resources, 2014.
Bibliographic record
Abstract
Reliable evaluation of fracture toughness resistance curves, including both J–resistance (J-R) and crack tip opening displacement–resistance (CTOD-R) curves, is becoming an integral part of pipeline integrity assessment for demanding applications. Using MTS TestSuite Software with Multipurpose Elite, we have successfully realized the automation of fracture toughness test procedures for single-edge bend [SE(B)] test specimens based on ASTM E1820-11 and BSI 7448. The software offers the option to use either load-line displacement (LLD) or crack mouth opening displacement (CMOD) as the control parameter for both shallow- and deep-cracked SE(B) specimens and exports both the J-R and the CTOD-R curves simultaneously. In order to validate the developed software, we have tested two different pipe steels, namely, X60 and X100 steels. The nominal initial crack lengths a/W after precracking were equal to 0.2 and 0.5 for the shallow- and deep-cracked specimens, respectively. A 10% deep side groove was machined after the precracking on each side of the specimen. The results show that for J-R curves, the differences between the LLD and CMOD methods are negligible within the Jmax criteria range. Beyond this range, however, some differences were observed. There was no significant effect of work hardening rate on the J-R curves obtained using either LLD or CMOD for the two pipe steel materials investigated. However, it is worth noting that there were large discrepancies between the ASTM and BSI methods in terms of CTOD-R curve measurements, especially for the shallow-cracked specimens. This was attributed to the fact that the standards use different definitions of CTOD.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.003 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".