Out-of-autoclave manufacturing of complex shaped composite laminates
Bibliographic record
Abstract
Out-of-Autoclave (OOA) manufacturing answers the growing need of the aerospace industry to process components of larger sizes at reduced costs. Recent prepreg materials have been developed specifically for OOA manufacturing and feature increased in-plane permeability through the presence of dry-fibre paths for efficient evacuation of gases. However, the differences in impregnation and resin kinetics attributed to OOA prepregs with respect to autoclave prepregs may affect the compaction behaviour in complex shape laminates. This thesis presents the results of an investigation of important design and processing parameters on the quality of complex shape laminates manufactured by OOA methods.L-shape composite laminates were manufactured by OOA methods, following the recommendations documented in the literature. The samples were tested for thickness variation at the corner and void content levels. The thickness variation at the corner was characterised based on the radius-to-thickness ratio for Cytec Cycom 5320 PW and 8HS prepregs with concave and convex tools. The experimental study showed increased corner thickening with decreasing radius-to-thickness ratio for both tool shapes. The data can be used to determine the minimal radius-to-thickness ratio for acceptable thickness variation for each material and serve as a design guideline. An analytical model of the compaction of L-shape laminates was developed. The discrepancies between the experimental data and the model predictions for thickness variation at the corner highlight the importance of shearing mechanisms in the compaction of L-shape laminates. Also, from the experimental investigation of various bagging arrangements, it is observed that the compaction at the corner is improved with the use of a pressure intensifier or pressure strip with proper corner radius. In addition, breather material should be placed under the pressure intensifier to allow efficient air removal and maintain a low void content level. A numerical analysis of the compaction of a laminate over a concave tool was performed and demonstrated that the material of the pressure intensifier or pressure strip should be of high stiffness for efficient laminate compaction.
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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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".