Bird Impact Simulation of Polycarbonate Windshield Subject to Brittle Failures
Bibliographic record
Abstract
Due to its low density, optical transparency, and ability to withstand large plastic deformations without failure, polycarbonate is being increasingly used as a structural material for light weight, impact resistant helicopter windshields. However, polycarbonate can exhibit brittle failure with degraded impact resistance when exposed to some types of high triaxial loads or high strain-rate loading conditions. This paper presents the state-of-the art simulation techniques developed at Bell Helicopter Textron Inc. (BHTI) to support the design of bird impact resistant windshields. Linear Elastic Fracture Mechanics (LEFM) methods were used to investigate mechanisms that can trigger the polycarbonate to exhibit brittle failure. Finite element simulations were conducted to explore the threshold conditions under which brittle failure can occur, and to correlate the material constitutive model against test data under a wide range of loading conditions and strain rates. The failure model of the polycarbonate material model was validated to reflect the specific loading conditions. The validated analytical tool provides the capability to design for equivalent or greater levels of impact protection using thinner and lighter polycarbonate and has been successfully used to guide the development of bird impact resistant windshields.
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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 | 0.000 |
| 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) | 0.000 | 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".