EXPERIMENTAL AND THEORETICAL INVESTIGATIONS ON THE VELOCITY OSCILLATIONS OF DYNAMIC CRACK PROPAGATING IN BRITTLE MATERIAL TENSION
Bibliographic record
Abstract
To study the propagating behavior of a dynamic crack in brittle material, an experimental technique was developed to measure the propagation of a fast crack in a preloaded brittle polymethylmethacrylate(PMMA) strip. The experimental results show that for each preloaded strip, the crack arrives at a steady velocity v0after a short acceleration stage, when the crack propagation is self-similar. The steady propagation velocity was found to be an increasing function of the energy Gc stored in the preloaded strip, which means that the material has a speed toughening property. When the crack exceeds a threshold, the crack exhibits apparent oscillations. This crack oscillation corresponds to the microscopic periodic grooves on the fractured surface. Further increase of the pre-stored elastic energy results in the curving, micro-branching, and full bifurcations of the cracks. Based on the energy conservation theory, a dynamic model is established to describe the motion of the crack. This motion equation is used to explain the crack oscillations during propagations.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 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".