Fatigue life prediction via the time‐dependent evolution of linear and nonlinear mechanical parameters determined via Fourier transform of the stress
Bibliographic record
Abstract
ABSTRACT This study proposes a new concept for the lifetime prediction of solid polymers under mechanical fatigue. The time evolution of linear and nonlinear mechanical parameters was studied using polystyrene (PS), polymethylmethacrylate (PMMA), and styrene‐acrylonitrile (SAN) samples in strain controlled (large amplitude) oscillatory shear (torsion). Higher harmonics of the stress were detected and quantified via Fourier transform (FT). Besides storage and loss modulus (G′, G″), the ratio of the third (I3) harmonic over the fundamental one, I1 (I3/1), was analyzed. After an initial transient period (regime I), the three parameters (G′, G″, and I3/1) linearly de/increase with the cycle number (N) (regime II) before failure onset (regime III) occurs. In regime II, the absolute values of the rates of change (derivative) of G′, G″, and I3/1 (dG′/dN, dG″/dN, and dI3/1/dN) were correlated with the lifetime (Nf). An inverse proportionality between the rate of change and lifetime was found allowing better prediction while testing. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46634.
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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 | 0.000 | 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 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".