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Cited by 6Acoustic Wave Phenomena ResearchAerospace, Electronics, Mathematical ModelingVehicle Noise and Vibration Control

Sustainable Perforated Acoustic Wooden Panels Designed Using Third-Degree-of-Freedom Bezier Curves with Broadband Sound Absorption Coefficients

Open access
Chojnacki, Bartlomiej, Schynol, Kamil, Halek, Mateusz, Muniak, Alicja·2023·Materials
DOI 10.3390/ma16186089PMC PMC10532742
Open this paper in CoChat — free accountOpen PDF

Abstract

The current interior design scope places high demands on acoustic treatment manufacturers. The state of the art does not provide satisfactory material proposals for architects to satisfy design needs. There is a need for a novel approach concerning decorative, recognized materials that adapts them to the acoustic surface properties. The final design proposed in this study presents a modern functional solution with high acoustic properties, which can be produced with sustainable materials such as FSC wood and has a low environmental impact because of its low waste production. This research presents the complete design process of a novel type of wooden acoustic panel. A comprehensive explanation of the scientific development is covered, including basic material testing in an impedance tube, FEM simulations of the initial designs, and final measurements in a reverberation chamber. The solution’s novelty is based on the optimized placement of the perforation holes on the surface of a wooden overlay using a ship deck optimization algorithm. The methods used cover the original solution of mixing FEM modeling of the surface impedance with the application of the Jeong–Thomasson correction for random incidence sound absorption coefficient simulation. The contribution of this research is the development of wooden perforated panels with Class A sound absorption and an overall depth of 90 mm, including the 50 mm depth of the backing material. The discussion will explain the difficulties of working with this material and the need for a combination of the aesthetic and acoustic sides of the project.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper develops sustainable perforated wooden acoustic panels with third-degree-of-freedom Bezier-curve front overlays, optimized via a ship-deck arrangement algorithm and simulated with FEM plus the Jeong–Thomasson correction. The final P-A and CM-A panels achieved Class A sound absorption per ISO 11654 with an overall depth of 90 mm, including 50 mm of porous backing.

Key findings

  • P-A and CM-A overlays demonstrated Class A sound absorption according to ISO 11654, while the CM-D overlay exhibited Class D; both P-A and CM-A reached values greater than 1.0 in the mid- and high-frequency ranges in reverberation chamber measurements.
  • FEM optimization concluded that a perforation rate over 25% and hole diameter no less than 6 mm should be attained for practical mid- and high-frequency absorption and potential Class A certification; lower perforation rates with approximately 3 mm holes can operate resonantly but cannot achieve broadband absorption higher than Class E or D.
  • Panels produced using third-degree curves with perforations exhibited slightly better acoustic properties than flat overlays across the measured frequency range; the 3D surface performed worse at low frequencies but improved average absorption significantly in mid- and high-frequency ranges.
  • Replacing 1/3 or 2/3 of perforated overlays with solid overlays reduced sound absorption and shifted the sound absorption class between A, C, and D.

Methods

  • Impedance tube tests followed ISO 10534-2 using a B&K type 4206 tube; 100 mm diameter samples were tested with 50 mm recycled-material-based fiberglass backing (density 50 kg/m³; flow resistivity around 32 kPa·s/m²) across flat and 3D panels with polished or brushed finishes.
  • FEM simulations used COMSOL Multiphysics 5.3 with Delany–Bazley porous modeling, thermoviscous acoustics for viscous loss in holes, averaged surface impedance, and the Jeong–Thomasson correction for random-incidence absorption; the upper frequency available to simulate was 550 Hz for the 500 mm sample, and a 3 × 3.5 m rectangular sample was used for α_size.
  • Perforation placement used a simplified ship deck arrangement algorithm with minimum 5 mm edge distance and 3 mm between hole edges; final panels were measured in a reverberation chamber per ISO 354 (chamber volume 180.4 m³, total surface 193.6 m², sample size 10.4 m², relative humidity 32.3–36.4%, temperature 22.2–23.1 °C).

Limitations

  • The paper states that FEM simulation was limited to an upper frequency of 550 Hz because of the 500 mm sample size, and that only normal incidence was considered before applying the Jeong–Thomasson correction.
  • The paper states that the CM-D panel’s measured absorption differed most from simulation, likely because plate absorber behavior was not included in the modeling; it concludes that lower-perforation-ratio panels require plate absorber mechanisms for precise simulation.
  • The paper states that ISO 354 values greater than 1.0 in mid- and high-frequency ranges can occur due to finite reverberation chamber volume, edge effects, sample surface calculation, and incompletely diffused sound fields; it also notes that multiple simulation patterns were not presented because of the large amount of data. Evident from the text: the authors assumed a flat panel surface for radiation impedance despite the 3D front shape.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/ma16186089

Cites

33 of 33 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

12 of 30 cited sources checked · 4 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    The research in [12] focused only on MPPs with a flat shape.

    “Also, their research was focused only on MPPs (micro-perforated panels) with a flat shape.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Sakagami, 2022, A Basic Study on the Design of Dotted-Art Heterogeneous MPP Sound Absorbers, Acoustics source
  • Interpretationcitation

    The solution's novelty is based on optimized placement of perforation holes on the surface of a wooden overlay using a ship deck optimization algorithm.

    “The solution’s novelty is based on the optimized placement of the perforation holes on the surface of a wooden overlay using a ship deck optimization algorithm.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [38] Wang, 2021, An Approach to Ship Deck Arrangement Optimization Problem Using an Improved Multiobjective Hybrid Genetic Algorithm, Math. Probl. Eng. source
  • Premisecitation

    Most current papers on acoustic panel development only cover analytical problem formulation or final design measurement in engineering reports.

    “Most of the current papers on acoustic panel development only cover the analytical problem formulation [7,8] or the final design measurement in the engineering reports [9,10,11].”
    Quote in the paperSubstantial claim4 of 5 sources checked
    • cites [7] Cox, 2017, Metadiffusers: Deep-Subwavelength Sound Diffusers, Sci. Rep. source

      The Introduction discusses earlier diffuser designs, while Results > Quadratic residue metadiffusers describes this paper’s theoretical predictions and numerical validation (page numbers unavailable). Neither passage assesses whether most acoustic-panel papers cover only analytical formulations or final design measurements. Searches for that characterization and for experimental design measurements found no supporting passage in our copy. (LLM, conf=0.73)

      Experimental — accuracy not yet measured
    • cites [8] Carbajo, 2015, A Finite Element Model of Perforated Panel Absorbers Including Viscothermal Effects, Appl. Acoust. source

      The Introduction (page unavailable) says numerous works model perforated-panel acoustics, supporting the analytical-modeling part of the claim. It does not say most current papers cover only analytical formulation or final-design measurement in engineering reports; it says most of the models discussed have also been experimentally validated. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [9] Kusaka, 2021, A Basic Study on the Absorption Properties and Their Prediction of Heterogeneous Micro-Perforated Panels: A Case Study of Micro-Perforated Panels with Heterogeneous Hole Size and Perforation Ratio, Acoustics source

      The Introduction (page unavailable) describes one prior study that compared analytical and numerical methods without reporting experimental results. It does not say that most acoustic-panel papers are limited to analytical formulation or final-design measurements in engineering reports. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites [10] Pilch, 2011, The Effect of Geometrical and Material Modification of Sound Diffusers on Their Acoustic Parameters, Arch. Acoust. source

      The Abstract (page not available in our copy) says the paper reports laboratory measurements of sound diffusers, so it can serve as an example of measurement-based acoustic-panel research. The paper does not establish that most current papers cover only analytical formulations or final-design measurements, nor does it characterize those measurements as engineering reports. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites [11] 2021, Experimental Tests of the Acoustic Properties of Sound-Absorbing Linings and Cores of Layered Baffles, Vib. Phys. Syst.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Study design and conductnone given

    The methods used include mixing FEM modeling of surface impedance with the Jeong-Thomasson correction for random incidence sound absorption coefficient simulation.

    “The methods used cover the original solution of mixing FEM modeling of the surface impedance with the application of the Jeong–Thomasson correction for random incidence sound absorption coefficient simulation.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites [26] Thomasson, 1980, On the absorption coefficient, Acustica

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [27] Jeong, 2009, A Correction of Random Incidence Absorption Coefficients for the Angular Distribution of Acoustic Energy under Measurement Conditions, J. Acoust. Soc. Am. source

      The paper’s title identifies it as a correction of random-incidence absorption coefficients, supporting the Jeong correction component. The available indexed passages do not identify a “Jeong–Thomasson correction” or describe combining that correction with FEM surface-impedance modeling. The sentence presents the FEM combination as the citing authors’ method, rather than necessarily attributing it to Jeong. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • The authors state this as an assumption: The panel surface can be assumed flat for applying radiation impedance.
    • The authors state this as an assumption: The local reaction assumption applies to the current absorber because it has acoustic perforations in its base.
  • Premisecitation

    Most currently used perforated panel designs are based on regular hole placement in a grid.

    “However, most currently used designs are based on a regular hole placement in the grid [2].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [2] Pereira, A., Gaspar, A., Godinho, L., Amado Mendes, P., Mateus, D., Carbajo, J., Ramis, J., and Poveda, P. (2021). On the Use of Perforated Sound Absorption Systems for Variable Acoustics Room Design. Buildings, 11. source

      The Introduction discusses perforation type, diameter, central distance, and perforation ratio, while Section 3 models a panel using the impedance of a single hole and its open-area ratio. Neither passage says that most current designs place holes in a regular grid; searches for grid and regular placement found no supporting passage. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
  • Classified as probably not a substantial claim. 16
  • May combine two claims. 10

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Research [14] used FEM modeling and reverberation chamber measurements, confirming the possibility of joint use of these methods.

    “Very comprehensive research is found in [14], where methods similar to those adopted in this paper were used, i.e., FEM modeling and reverberation chamber measurements, confirming the possibility of the joint use of these methods.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [14] Hoshi, 2020, Implementation Experiment of a Honeycomb-Backed MPP Sound Absorber in a Meeting Room, Appl. Acoust. source

  • May combine two claims.

    Premisecitation

    The authors of [12] investigated non-uniform perforation patterns in impedance tubes but presented no further reverberation chamber measurements.

    “The authors of [12] investigated some non-uniform perforation patterns in impedance tubes. However, no further reverberation chamber measurements were presented.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [12] Sakagami, 2022, A Basic Study on the Design of Dotted-Art Heterogeneous MPP Sound Absorbers, Acoustics source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Irregular hole placement is not common.

    “However, irregular hole placement is not common [2,3].”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [2] Pereira, A., Gaspar, A., Godinho, L., Amado Mendes, P., Mateus, D., Carbajo, J., Ramis, J., and Poveda, P. (2021). On the Use of Perforated Sound Absorption Systems for Variable Acoustics Room Design. Buildings, 11. source

      The Sound Absorption Evaluation section discusses perforation rate and interactions between holes, but does not say whether irregular hole placement is common. Searches for irregular, non-uniform, and regular hole arrangements found no passage addressing how frequently they are used. (LLM, conf=0.72)

      Experimental — accuracy not yet measured
    • cites [3] Liu, J., Guo, H., and Wang, T. (2020). A Review of Acoustic Metamaterials and Phononic Crystals. Crystals, 10. source

      Section 4.5 describes periodic inclusions, and the references list periodic structures, but neither addresses how common irregular hole placement is. Searches for “irregular hole placement,” “holes,” and nonperiodic arrangements found no passage establishing the claimed frequency. (LLM, conf=0.74)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    The influence of different finishing options for flat panels is significant, while for 3D panels it seems negligible.

    “The influence of different finishing options for flat panels is significant, while for 3D panels, it seems to be neglectable.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The developed wooden perforated panels have Class A sound absorption and an overall depth of 90 mm, including 50 mm backing material.

    “The contribution of this research is the development of wooden perforated panels with Class A sound absorption and an overall depth of 90 mm, including the 50 mm depth of the backing material.”
    • Also stated in: § 5. Summary · plain
      “The contribution of this research is the development of 3D wooden perforated panels with Class A sound absorption and an overall panel depth of 90 mm (50 mm of porous backing included), significantly improving the current base of acoustic materials.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Reducing the number of perforated overlays and replacing them with solid overlays decreased the sound absorption coefficient and shifted the sound absorption class.

    “As observed, reducing the number of perforated overlays and replacing them with solid overlays decreased the sound absorption coefficient, shifting the sound absorption class.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The selected material types do not allow for acoustic panel formulation using micro-perforated panels or metamaterial absorbers.

    “The selected material types do not allow for acoustic panel formulation using micro-perforated panels or metamaterial absorbers, so a new adaptation of classic perforated panels should be investigated.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based).

    Premisenone given

    Typical perforated panels with regular perforation patterns do not meet current aesthetic needs in the modern interior design market.

    “Typical perforated panels with regular perforation patterns do not meet the current aesthetic needs in the modern interior design market, and novel material development is needed.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    The final design can be produced with sustainable materials such as FSC wood and has low environmental impact because of low waste production.

    “The final design proposed in this study presents a modern functional solution with high acoustic properties, which can be produced with sustainable materials such as FSC wood and has a low environmental impact because of its low waste production.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    The two-microphone impedance tube method was applied according to ISO 10534-2, and the B&K Impedance tube type 4206 complied with standard requirements.

    “To measure the acoustic absorption of panels, the two-microphone impedance tube method was applied according to the ISO 10534-2 standard [22]. The hardware used was a B&K Impedance tube (type 4206), which complied with the standard requirements.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [22] (1998). Acoustics—Determination of Sound Absorption Coefficient and Impedance in Impedance Tubes—Part 2: Transfer- Function Method (Standard No. ISO 10534-2:1998).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Reference [13] used non-uniform perforation pattern modeling to investigate artistic application of acoustic perforated panels and presented only impedance tube measurements.

    “Reference [13] also used the non-uniform perforation pattern modeling approach to investigate the possibility of the artistic application of acoustic perforated panels. In that study, only impedance tube sound absorption measurements were presented.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [13] Lee, H.P., Kumar, S., and Aow, J.W. (2021). Proof-of-Concept Design for MPP Acoustic Absorbers with Elements of Art. Designs, 5. source

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Wooden 3D panels using third-degree curves are not included in the current state of the art.

    “Wooden 3D panels using third-degree curves are not included in the current state of the art, meaning that initial testing is required, including impedance tube material measurements, to verify the possible influence of the complex front panel shape on the acoustic absorption.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Including MPP-type perforation in solid wood materials is complicated.

    “The research in [14] also focused on MPPs, but it was found that including this type of perforation in solid wood materials is complicated [15,16].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [15] Smardzewski, 2015, Sound Absorption of Wood-Based Materials, Holzforschung source
    • cites [16] Smardzewski, J., and Kamisiński, T. (2016). Właściwości Akustyczne Materiałów Stosowanych w Meblarstwie, Wydawnictwo Uniwersytetu Przyrodniczego.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The upper frequency available to simulate was 550 Hz due to the total sample size diameter of 500 mm.

    “Concerning the total sample size diameter (500 mm), the upper frequency available to simulate was 550 Hz.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    High prototyping costs make final reverberation chamber product testing unprofitable.

    “Advanced shapes in perforated panel materials are uncommon [6] as their performance is difficult to predict, while the high prototyping costs make the final reverberation chamber product testing unprofitable.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    There is a lack of comprehensive process formulation in acoustic material development for wooden perforated panels with irregular perforation patterns, from initial design to modeling including FEM and final prototype testing.

    “There is a lack of comprehensive process formulation in acoustic material development for wooden perforated panels with irregular perforation patterns, from the initial design to the modeling phase, including FEM modeling and the final prototype testing.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    A rectangular sample of 3 × 3.5 m was used for αsize because it reflected the required conditions for later ISO 354 measurements.

    “For αsize, a rectangular sample was used with a size of 3 × 3.5 m as it reflected the required conditions for the later ISO 354 [37] measurements.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [37] (2003). Acoustics—Measurement of Sound Absorption in a Reverberation Room (Standard No. ISO 354).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationown data

    A perforation rate of over 25% and a hole diameter of no less than 6 mm should be attained to achieve practical sound absorption values in the mid- and high-frequency ranges.

    “(a)A perforation rate of over 25% and a hole diameter of no less than 6 mm should be attained to achieve practical sound absorption values in the mid- and high-frequency ranges.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The minimum distance between hole edges of 3 mm is safe for panel consistency.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    The modification of including non-perforated overlays can be applied easily, even after mounting in in situ conditions.

    “This modification can be applied easily, even after mounting in in situ conditions, which may provide unique features for variable acoustic applications with wooden perforated panels.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The rest of the panel properties, such as FSC wood certification and ecological and recycling aspects, allow these materials to be used in modern architecture.

    “The rest of the panel properties, such as the FSC wood certification and the ecological and recycling aspects, allow these materials to be used in modern architecture.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    For panels with lower perforation rates, achieving a wideband characteristic and obtaining a sound absorption class higher than E or D are impossible.

    “However, achieving a wideband characteristic and obtaining a sound absorption class higher than E or D are impossible.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The ISO 354 standard is required for any acoustic panel certification.

    “These effects cannot be obeyed, while the ISO 354 standard is required for any acoustic panel certification, and its procedure needs to be precisely followed.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [37] (2003). Acoustics—Measurement of Sound Absorption in a Reverberation Room (Standard No. ISO 354).

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

22 of 22

  • The authors state this as an assumption.

    The panel surface can be assumed flat for applying radiation impedance.

    “In this paper, we assumed the panel surface to be flat and followed a similar approach for a different material: a wooden 3D perforated panel with a porous backing.”

  • The authors state this as an assumption.

    The local reaction assumption applies to the current absorber because it has acoustic perforations in its base.

    “Equation (6) is valid with the assumption of a local reaction, which applies to the current absorber as it has acoustic perforations in its base.”

  • The authors state this as an assumption.

    The minimum distance between hole edges of 3 mm is safe for panel consistency.

    “The optimization parameters considered the minimum distance from the overlay edges to be 5 mm and the minimum distance between the hole edges to be 3 mm, which was assumed to be safe for panel consistency.”

  • The authors state this as an assumption.

    The panel design should maintain the visual aspects of the panel while adding sound-absorbing properties.

    “The assumption for the panel design was to maintain the visual aspects of the panel while adding sound-absorbing properties to it.”
4 of 4

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Surface impedance is called normalized but defined without normalization

    Minor

    Equation (6) identifies ZS as normalized surface impedance, while Equation (7) defines it as pressure divided by velocity. With the stated meanings of pressure and velocity, that ratio has impedance units rather than being normalized.

  • 3D panels are described as both better throughout the range and worse at low frequencies

    Minor

    The claim that the 3D panels performed better across the measured frequency range conflicts with the statement that they performed worse in the low-frequency range.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Cox, T.J., and D’antonio, P. (2009). Acoustic Absorbers and Diffusers: Theory, Design and Application, CRC Press.
  2. Vercammen, M., and Lautenbach, M. (2016, January 5–9). Isotropy and Diffuseness in Room Acoustics: Non Diffuse Sound Field in the Reverberation Room. Proceedings of the 22nd International Congress on Acoustics, Buenos Aires, Argentina. ICA2016-777.

Cited by

Sorted by citations

Related

Authors
Chojnacki, B., Schynol, K., Halek, M., & Muniak, A.
Affiliations
  • Department of Mechanics and Vibroacoustics, AGH University of Science and Technology, Mickiewicza Av. 30, 30-059 Cracow, Poland
  • Form At Wood sp. z o.o., Technologiczna 2, 45-839 Opole, Poland
  • AGH University of Krakow (PL)
ORCID
Chojnacki, Bartlomiej
Venue
Materials
Publisher
MDPI AG
Published
2023-09-06
Volume
16
Issue
18
Pages
6089
ISSN
1996-1944 (ISSN-L)
DOI
10.3390/ma16186089
PMC
PMC10532742
OpenAlex
W4386475950
Semantic Scholar
62d19042926b6695246a77f81b44b55bb1ee7b90
Cited by
6
References
32
Citations by year
2026: 1 · 2025: 2 · 2024: 2 · 2023: 1
FWCI
0.44
Type
journal article
Language
en
Open access
Licence
Locations
  • Materials (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
Funders
  • Opolskie Voivodeship Regional Operational Program (2014-2020, RPOP.01.01.00-16-0016/20)
  • Priority Axis I Innovation in Enterprises (2014-2020, RPOP.01.01.00-16-0016/20)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Acoustic Wave Phenomena Research
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Aerospace, Electronics, Mathematical Modeling
  • Physical Sciences › Engineering › Automotive Engineering › Vehicle Noise and Vibration Control
Keywords
wood panels, sound absorption, broadband absorption, sustainable construction materials, surface impedance, finite element analysis, reverberation chamber measurements, impedance tube, acoustic treatment

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-18.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-18.

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Statistics and arithmetic are recomputed, not judged.

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