Sound absorption performance of double layer sandwich structure containing micro-perforations and extended necks
Bibliographic record
Abstract
In this study, a double layer sandwich panels made of micro-perforated plate and perforated plate with extended necks is proposed and its acoustic attenuation is studied using the finite element method. The top panel of the structure is micro-perforated and is connected to a first honeycomb structure cells. The internal panel is perforated, and a neck is connected to each perforation and extends into each cell cavity of the second honeycomb structure. The proposed material design is made of 33 micro-perforations and 33 extended necks and has excellent mechanical stiffness due to the honeycomb structure performance. This study shows how to design the parameters of the necks and the micro-perforations to widen the sound absorption frequency band. With identical micro-perforation diameters and identical necks, the sound absorption coefficient presents two resonance peaks where the surface impedance is close to the impedance of air. The number of the sound absorption peaks increases when different micro-perforation diameters and different necks are used while the sound absorption of conventional double layer sandwich structure is zero over the entire frequency range. The proposed material design can be used to attenuate the noise in various engineering fields that require good bending stiffness.
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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) | 0.000 | 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".