Dynamic Analysis of Pitch Plane Railway Vehicle-Track Interactions Due to Single and Multiple Wheel Flats
Bibliographic record
Abstract
The dynamic impact forces due to the wheel defect such as a flat is a main concern for a heavy freight train operating at high speed. The present investigation employs a pitch plane vehicle model coupled with a comprehensive three-layer track system model to study the impact force generated in the wheel-rail interface due to the presence of wheel flats. The wheel-rail contact is modeled using nonlinear Hertzian contact theory. Responses in terms of wheel-rail impact load and forces transmitted to bearings, pad and ballast are evaluated in an attempt to identify desirable design and operating factors. Wheel-rail impact loads due to the presence of multiple flats either in single or different wheels in-phase or out-of-phase conditions are evaluated and analyzed. A detailed parametric study is carried out that includes the variations in selected vehicle, track, operational as well as flat parameters. The results show that the effect of multiple flats is insignificant if they are more than 45° apart. The impact due to single wheel flat can be larger than in-phase flats at each wheel due to the presence of pitch dynamics. The parametric study shows that other than speed, depth and length of the flats are most sensitive parameters, and there exists a critical length at each flat depth that leads to the largest impact load.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".