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Opiela K.C., Dauchez N.♦, Boutin T.♦, Bécot F.-X., Chevillotte F.♦, Venegas R.♦, Zieliński T.G., Comparison of double-porosity sound absorbers made of sintered or glued powder grains,
ISMA2024 / USD2024, 31st International Conference on Noise and Vibration Engineering / International Conference on
Uncertainty in Structural Dynamics, 2024-09-09/09-11, Leuven (BE), pp.337-346, 2024Streszczenie: Selective laser sintering and binder jetting are two additive manufacturing technologies that use loose powder as a feedstock. In the case of binder jetting, the printout walls are essentially permeable and need to be additionally impregnated to be fully air-tight. The permeability of sintered objects, on the other hand, can be controlled to some extent by the amount of laser energy, among other things, provided to the exposed layer. Exploring these two technologies, several single- and double-porosity samples were additively manufactured, examined and acoustically measured in an impedance tube. Moreover, the normal incidence sound absorption spectra resulting from these structures were predicted employing multi-scale methods. The values of porosity and permeability of permeable printed materials were determined and utilised in the applied modelling. It is observed that making the skeleton microporous and permeable enables effective sound absorption even in primitive 3D printed acoustic treatments. Afiliacje autorów:
Opiela K.C. | - | IPPT PAN | Dauchez N. | - | Sorbonne University Alliance (FR) | Boutin T. | - | Sorbonne University Alliance (FR) | Bécot F.-X. | - | IPPT PAN | Chevillotte F. | - | MATELYS – Research Lab (FR) | Venegas R. | - | MATELYS – Research Lab (FR) | Zieliński T.G. | - | IPPT PAN |
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Zielinski T.G., Opiela K.C., Dauchez N.♦, Boutin T.♦, Galland M.-.A.♦, Attenborough K.♦, Low frequency absorption by 3D printed materials having highly tortuous labyrinthine slits in impermeable or microporous skeletons,
10th Convention of the European Acoustics Association - Forum Acusticum 2023, 2023-09-11/09-15, Torino (IT), DOI: 10.61782/fa.2023.0342, pp.2275-2282, 2023Streszczenie: The low frequency peaks in the absorption spectra of layers of conventional porous materials correspond to quarter wavelength resonances and the peak frequencies are determined essentially by layer thickness. If the layer cannot be made thicker, the frequency of the peak can be lowered by increasing the tortuosity of the material. Modern additive manufacturing technologies enable exploration of pore network designs that have high tortuosity. This paper reports analytical models for pore structures consisting of geometrically complex labyrinthine networks of narrow slits resembling Greek meander patterns. These networks offer extremely high tortuosity in a non-porous solid skeleton. However, additional enhancement of the low frequency performance results from exploiting the dual porosity pressure diffusion effect by making the skeleton microporous with a significantly lower permeability than the tortuous network of slits. Analytical predictions are in good agreement with measurements made on two samples with the same tortuous slit pattern, but one has an impermeable skeleton 3D printed from a photopolymer resin and the other has a microporous skeleton 3D printed from a gypsum powder. Słowa kluczowe: sound absorption, high tortuosity, dual porosity, 3D printed materials Afiliacje autorów:
Zielinski T.G. | - | IPPT PAN | Opiela K.C. | - | IPPT PAN | Dauchez N. | - | Sorbonne University Alliance (FR) | Boutin T. | - | Sorbonne University Alliance (FR) | Galland M.-.A. | - | École Centrale de Lyon (FR) | Attenborough K. | - | The Open University (GB) |
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Zieliński T.G., Dauchez N.♦, Boutin T.♦, Chevillotte F.♦, Bécot F.-X.♦, Venegas R.♦, 3D printed axisymmetric sound absorber with double porosity,
ISMA2022 / USD2022, International Conference on Noise and Vibration Engineering / International Conference on Uncertainty in Structural Dynamics, 2022-09-12/09-14, Leuven (BE), pp.462-476, 2022Streszczenie: This paper shows that specific additive manufacturing (AM) technology can be used to produce double-porosity acoustic materials where main pore networks are designed and a useful type of microporosity is obtained as a side effect of the 3D printing process. Here, the designed main pore network is in the form of annular pores set around the axis of the cylindrical absorber. In this way, the axial symmetry of the problem is ensured if only plane wave propagation under normal incidence is considered, which allows for modelling with purely analytical expressions. Moreover, the outermost annular pore is bounded by the wall of the impedance tube used to measure the sound absorption of the material, so that experimental tests can be easily performed. Two different AM technologies and raw materials were used to fabricate axisymmetric absorbers of the same design, in one case obtaining a material with double porosity, which was confirmed by the results of multi-scale calculations validated with acoustic measurements. Afiliacje autorów:
Zieliński T.G. | - | IPPT PAN | Dauchez N. | - | Sorbonne University Alliance (FR) | Boutin T. | - | Sorbonne University Alliance (FR) | Chevillotte F. | - | MATELYS – Research Lab (FR) | Bécot F.-X. | - | MATELYS – Research Lab (FR) | Venegas R. | - | MATELYS – Research Lab (FR) |
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Zieliński T.G., Dauchez N.♦, Boutin T.♦, Leturia M.♦, Wilkinson A.♦, Chevillotte F.♦, Bécot F.-X.♦, Venegas R.♦, 3D printed sound-absorbing materials with double porosity,
INTER-NOISE 2022, 51st International Congress and Exposition on Noise Control Engineering, 2022-08-21/08-24, Glasgow (GB), pp.773-1-10, 2022Streszczenie: The paper shows that acoustic materials with double porosity can be 3D printed with the appropriate design of the main pore network and the contrasted microporous skeleton. The microporous structure is obtained through the use of appropriate additive manufacturing (AM) technology, raw material, and process parameters. The essential properties of the microporous material obtained in this way are investigated experimentally. Two AM technologies are used to 3D print acoustic samples with the same periodic network of main pores: one provides a microporous skeleton leading to double porosity, while the other provides a single-porosity material. The sound absorption for each acoustic material is determined both experimentally using impedance tube measurements and numerically using a multiscale model. The model combines finite element calculations (on periodic representative elementary volumes) with scaling functions and analytical expressions resulting from homogenization. The obtained double-porosity material is shown to exhibit a strong permeability contrast resulting in a pressure diffusion effect, which fundamentally changes the nature of the sound absorption compared to its single-porosity counterpart with an impermeable skeleton. This work opens up interesting perspectives for the use of popular, low-cost AM technologies to produce efficient sound absorbing materials. Afiliacje autorów:
Zieliński T.G. | - | IPPT PAN | Dauchez N. | - | Sorbonne University Alliance (FR) | Boutin T. | - | Sorbonne University Alliance (FR) | Leturia M. | - | Sorbonne University Alliance (FR) | Wilkinson A. | - | Sorbonne University Alliance (FR) | Chevillotte F. | - | MATELYS – Research Lab (FR) | Bécot F.-X. | - | MATELYS – Research Lab (FR) | Venegas R. | - | MATELYS – Research Lab (FR) |
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Zieliński T.G., Opiela K.C., Pawłowski P., Dauchez N.♦, Boutin T.♦, Kennedy J.♦, Trimble D.♦, Rice H.♦, Differences in sound absorption of samples with periodic porosity produced using various Additive Manufacturing Technologies,
ICA 2019, 23rd International Congress on Acoustics integrating 4th EAA Euroregio 2019, 2019-09-09/09-13, Aachen (DE), DOI: 10.18154/RWTH-CONV-239456, pp.4505-4512, 2019Streszczenie: With a rapid development of modern Additive Manufacturing Technologies it seems inevitable that they will sooner or later serve for production of specific porous and meta-porous acoustic treatments. Moreover, these new technologies are already being used to manufacture original micro-geometric designs of sound absorbing media in order to test microstructure-based effects, models and hypothesis. In the view of these statements, this work reports differences in acoustic absorption measured for porous specimens which were produced from the same CAD-geometry model using several additive manufacturing technologies and 3D-printers. A specific periodic unit cell of open porosity was designed for the purpose. The samples were measured acoustically in the impedance tube and also subjected to a thorough microscopic survey in order to check their quality and look for the discrepancy reasons. Słowa kluczowe: Sound absorption, Additive Manufacturing Technologies Afiliacje autorów:
Zieliński T.G. | - | IPPT PAN | Opiela K.C. | - | IPPT PAN | Pawłowski P. | - | IPPT PAN | Dauchez N. | - | Sorbonne University Alliance (FR) | Boutin T. | - | Sorbonne University Alliance (FR) | Kennedy J. | - | Trinity College (IE) | Trimble D. | - | Trinity College (IE) | Rice H. | - | Trinity College (IE) |
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