Numerical Assessment on the Mechanical Performance of Pressure Pipe CIPP Liner with Local Defects in the Outer Host Pipe
Bibliographic record
Abstract
Due to technical, economic and logistical factors, cured in place pressure pipe (CIPP) liner systems have become one of the preferred options to rehabilitate damaged, ageing water pipe.There is a need to better understand the mechanical performance and limit states of the CIPP liner across a range of practical design parameters.In this study, the three-dimensional continuum finite element analysis was conducted to assess the effects of local defects in the host pipe on the mechanical performance of the CIPP liner subject to internal pressure, axial deformation and flexure loading conditions.For a CIPP liner subject to internal pressure with local circular void defects in the host pipe, the limit state was governed by axial tension when the defect diameter to CIPP diameter (d/D) ratio was greater than 0.4.A yield response was observed for the higher liner diameter to wall thickness ratios (D/t > 60) and hoop stress to yield ratios (σh/σy ≥ 0.6).The effects of a circumferential gap defect on the CIPP liner mechanical response were evaluated.For internal pressure loading, the longitudinal distribution of normalized radial displacement for the CIPP liner was primarily influenced by the width of the circumferential gap defect width to CIPP liner diameter (g/D) and the CIPP D/t ratio.The CIPP liner mechanical performance with circumferential gap defects in the host pipe when subject to internal pressure and pipe rotation was also investigated.The defect gap ratio (g/D) had an impact on the CIPP liner deformation pattern.The host pipe/CIPP liner interface friction coefficient had a negligible effect due to the mobilization of a virtual anchor.
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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 | 0.001 | 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".