Outer Surface Prior to Inner Surface Double Autofrettage Technique for a Compound Cylinder
Bibliographic record
Abstract
The autofrettage and shrink-fit processes are used to enhance the load carrying capacity and fatigue life of the pressure vessels. Previous works were mainly concerned with increasing the compressive residual stress at the near bore area of the compound cylinders, ignoring the harmful high tensile residual stress developed at the outer part of the cylinder. Also, the idea of multiple or re-autofrettage had been only used at the inner surface of the cylinder to increase the magnitude of compressive residual stress at the near bore area. In this study, a new design approach is proposed by applying an autofrettage cycle on the external surface of the cylinder prior to an autofrettage cycle on the internal surface of the cylinder. It is shown that this double autofrettage cycle not only increases the magnitude of compressive residual stress at the near bore area but also decreases the tensile residual stress at the near outer surface area. Moreover, the proposed double autofrettage process has been combined with shrink-fit and standard inner surface autofrettage processes to produce new combinations of a two-layer compound cylinder. The fatigue life for these new combinations has been evaluated to verify the improvement while using the double autofrettage process.
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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 | 0.000 |
| 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) | 0.001 | 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".