Modeling Time-Dependent Behavior of Medium-Density Polyethylene Pipes
Bibliographic record
Abstract
Medium-density polyethylene (MDPE) pipes are widely used for gas transmission and distribution systems. The behavior of the pipes buried in the ground is governed by soil–pipe interaction. MDPE possesses a time-dependent material property that influences the pipe–soil interaction over time. The current industry practice to account for the time-dependent effect uses secant moduli to calculate the short-term and long-term responses. This method ignores the effect of loading rate, which can have a significant effect on the pipe responses. In the current study, a rigorous finite-element (FE) analysis is employed to investigate the effect of the rate of loading on the pipe behavior. An FE modeling framework for MDPE, developed earlier by the authors, is employed in this study. Two problems, one on a conventional buried pipe subjected to ground and surface load and the other on a pipeline subjected to rate-dependent lateral ground movement, are considered. Based on the investigation, a feasible method of accounting for the time-dependent behavior of MDPE for the pipe–soil interaction problems is developed.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".