Sound attenuation performance at high sound pressure level of micro-perforated panel sound absorber with embedded resistive screen
Bibliographic record
Abstract
To enlarge the sound absorption frequency band of micro perforated panel (MPP) absorbers, a composite sound absorber made of an MPP, an air cavity with embedded resistive screens and a rigid back plate is proposed and studied at high sound pressure level (SPL).The sound absorption coefficient predicted theoretically is compared with the experimental measurement at 150 dB and a good agreement is obtained.With one layer of resistive screen within the air cavity, the sound absorption coefficient is significantly improved over a large frequency band and remains almost identical with respect to the SPL compared to a classical MPP absorber whose sound absorption frequency band is narrow with a resonant peak that varies with the SPL.When two resistive screens layers are embedded within the air cavity, the absorption frequency band is further improved.The impacts of the perforation ratio of the MPP on the sound absorption performance are illustrated.A sensitivity analysis shows that the resistance per unit area of the screen affects the acoustic properties of the absorber at low SPL while at high SPL, the acoustic properties are mainly controlled by the perforation ratio of the MPP and the acoustic orifice Mach number.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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".