Bibliographic record
Abstract
This article presents a synthesis of the Transportation Safety Board of Canada's (TSB) report on the brittle fracture of the hull of Lake Carling, and concludes with an overview of the TSB's safety concern on brittle fracture in ships, including ongoing initiatives at the International Maritime Organization. The TSB is an independent agency created to advance transportation safety through the investigation of occurrences in the marine, pipeline, rail and air modes of transportation. The majority of the world's civilian cargo vessels have side shells constructed with steel of unqualified toughness (grade A steel). In 2002 and 2003, respectively, samples of side shell steel from Lake Carling and a sister ship, Ziemia Gornoslaska (ex-Lake Charles), were made available to the TSB. Steel from both vessels had very poor fracture arrest toughness (low Charpy Vee Notch energies) at temperatures near 0°C. The relatively low fracture toughness of the side shell plate of Lake Carling, when exposed to near 0°C temperatures, allowed a pre-existing crack at frame 91 to grow to failure at a load well below the ultimate tensile strength of the material. Given the uncertainties and variability of fracture arrest toughness for some grade A and B steels, it would appear that residual risks for unstable brittle fracture are still present in vessels with hulls constructed with these steels, especially when operating in colder climates. Because there are no International Association of Classification Societies Ltd. Unified Requirements to use steel of qualified toughness in way of a vessel's side shell, the risk of brittle fracture can be perpetuated in a significant proportion of new buildings. Given the gravity of consequences of brittle fracture, the establishment of a standard is desirable. The standard should be rigorous enough to ensure that steel toughness would be adequate under all expected operating conditions such that a reasonable damage tolerance can be predicted and relied upon.
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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 | 0.004 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.003 | 0.008 |
| Scholarly communication | 0.003 | 0.006 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.004 | 0.004 |
| Insufficient payload (model declined to judge) | 0.006 | 0.003 |
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".