Spallation-based numerical simulation of ice-induced vibration of a structure
Bibliographic record
Abstract
A full-scale numerical simulation model of ice-induced vibration of structures has been developed (using LS-Dynaᵀᴹ) and applied to the Molikpaq facility for an ice-encroachment event similar to that which occurred on May 12,1986 in the Beaufort Sea. The bulk ice sheet used for the simulations had elastic properties, and its dimensions were 6 km x 6 km x 2.5 m. Where ice crushing occurred at the structure-ice interface the ice model used was a crushable foam that incorporated regular spallation events. Typical characteristics of ice-crushing in the brittle regime were manifested by the model. That is, a narrow horizontal hard zone (relativelyintact high-interface-pressure ice) was present in the mid-height region of the ice-edge contact area. Soft-zone material (shattered spall debris from the hard zone) was also represented. Evolution of the hard-zone contact area involved rapid reductions in size during spallation events, immediately followed by fast growth during consequent elastic surging of the near-field ice sheet and structure towards each other, and then some slower growth (due to the bulk icesheet velocity) until the next spalling event. The specified ‘thickness’ of the spalls was 5.4 cm, as previously determined from Molikpaq records of the frequency of the spalling events as a function of ice-sheet speed. Spallation (and associated rapid drops in load) occurred at regular intervals whenever a critical amount of hard-zone stress was reached at the ice-structure interface. The amplitude of the Molikpaq repetitive movements in response to the sawtooth loading from the spalling events depended on whether the resonant frequency of the structure/ice system was higher (for a strong response) or lower (for a weak response) than the spalling frequency, where the spalling frequency is directly proportional to the ice-sheet speed. The continuously variable resonant frequency of the structure/ice system had a maximal limiting value (~ 2.1 Hz), designated as the At-Spallation-Resonant-Frequency (ASRF), that was essentially determined by the time duration of load drops at spallation events. The simulations inherently accounted for the variable effective mass and effective spring constant of the ice sheet.
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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 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.002 | 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".