Numerical simulation of rheological effects in fiber spinning
Bibliographic record
Abstract
The fiber-spinning process is an important industrial operation to manufacture synthetic fibers. The process occurs under free-surface conditions, and the final properties of the fiber are characterized by the extensional properties of the polymer. Specifically, the non-isothermal response of the polymer in uniaxial extension dominates the process. The fiber-spinning process is analyzed by means of a unidirectional approach because the thickness of the fiber is very small with respect to its lateral dimension. The analysis accounts for the prehistory of the material inside the die, based on purely extensional strains. For viscoelastic polymer melts, the constitutive equation must be able to describe adequately the rheological behavior of the polymer in extensional flow. A good candidate for such modeling is the K-BKZ integral constitutive equation, with a spectrum of relaxation times, which captures well the nonlinear viscoelastic response of polymer melts. The non-isothermal response is taken into account with a temperature shift factor utilizing the Morland-Lee hypothesis. The present work includes effects due to gravity, inertia, and air drag, where applicable. Simulation results are compared with experiments on polypropylene (PP), poly(ethylene terephthalate) (PET), and low-density polyethylene (LDPE) melts at low and high speeds. Results are also compared with previous simulations. It is shown that in some cases the extrudate swell at the spinneret exit must be taken into account to accurately predict the drawing forces, which makes a fully two-dimensional analysis a necessity for such operations. © 2000 John Wiley & Sons, Inc. Adv Polym Techn 19: 155–172, 2000
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".