Investigation on the effect of coulomb friction on nose landing gear shimmy
Bibliographic record
Abstract
Landing gear shimmy remains a challenge in aircraft design despite abundant advances in aircraft engineering in the past few decades. Accurate shimmy prediction is closely tied to availability of dynamic models with all relevant types of motions and key nonlinear elements, a matter which has been accomplished in the present study through including rotational, lateral, longitudinal, and axial degrees of freedom and tire, shock absorber, and Coulomb friction nonlinearities. Using multi-body dynamic simulations, stability of the nose landing gear is studied as a function of key system parameters. Influences of nonlinearities are investigated in isolation, with a more in-depth look at the Coulomb friction effect, which is modeled as a function of the shock absorber stroke rate and rotational shimmy speed. It is found that Coulomb friction is a key factor in determining the onset and type of shimmy. The effect of friction parameters is then studied using nonlinear sensitivity analyses, and witnessed trends are utilized to draw design recommendations.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.001 | 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".