Instytut Podstawowych Problemów Techniki
Polskiej Akademii Nauk

Partnerzy

S. Ahsani

Katholieke Universiteit Leuven (BE)


Prace konferencyjne
1.  Ahsani S., Boukadia R.F., Droz C., Zieliński T.G., Jankowski Ł., Claeys C., Desmet W., Deckers E., On the potential of meta-poro-elastic systems with small mass inclusions to achieve broad band a near-perfect absorption coefficient, ISMA2020 / USD2020, International Conference on Noise and Vibration Engineering / International Conference on Uncertainty in Structural Dynamics, 2020-09-07/09-09, Leuven (BE), pp.2463-2472, 2020

Streszczenie:
This paper discusses the potential of meta-poro-elastic systems with small mass inclusions to create broadband sound absorption performance under the quarter-wavelength limit. A first feasibility study is done to evaluate whether embedding small mass inclusions in specific types of foam can lead to near-perfect absorption at tuned frequencies. This paper includes an optimization routine to find the material properties that maximize the losses due to the mass inclusion such that a near-perfect/perfect absorption coefficient can be achieved at specified frequencies. The near-perfect absorption is due to the mass-spring effect, which leads to an increase in the viscous loss. Therefore, it is efficient in the viscous regime. The well-known critical frequency, which depends on the porosity and flow resistivity of the material, is commonly used as a criteria to distinguish the viscous regime from the inertial regime. However, for the types of foam of interest to this work, the value of critical frequency is below the mass-spring resonance frequency. Hence, the inverse quality factor is used to provides a more accurate estimation on the frequency at which the transition from the viscous regime to the inertial regime.

Afiliacje autorów:
Ahsani S. - Katholieke Universiteit Leuven (BE)
Boukadia R.F. - inna afiliacja
Droz C. - inna afiliacja
Zieliński T.G. - IPPT PAN
Jankowski Ł. - IPPT PAN
Claeys C. - Katholieke Universiteit Leuven (BE)
Desmet W. - Katholieke Universiteit Leuven (BE)
Deckers E. - Katholieke Universiteit Leuven (BE)
20p.
2.  Ahsani S., Deckers E., Zieliński T.G., Jankowski Ł., Claeys C., Desmet W., Absorption enhancement in poro-elastic materials by mass inclusion, exploiting the mass-spring effect, SMART 2019, 9th ECCOMAS Thematic Conference on Smart Structures and Materials, 2019-07-08/07-11, Paris (FR), pp.1076-1084, 2019

Streszczenie:
In this paper the possibility of enhancing the absorption coefficient of a poro-elastic material using small, elastic mass inclusions in frequencies lower than the quarter-wavelength resonance of the porous material is discussed. We show that absorption peaks can be achieved not only by what is known in literature as the trapped mode effect, but also by the resonance of small elastic inclusions at low frequencies, which can be interpreted as a mass-spring effect. In this work, the inclusion and the porous skeleton is considered elastic and fully coupled to each other, therefore accounting for all types of energy dissipation i.e. viscous, thermal, and structural losses and energy dissipated due to the relative motion of the fluid phase and the frame excited by the resonating inclusion. Additionally, the inclusions are also modeled as motionless and rigid to distinguish between the trapped mode and/or the modified frame mode effect and the mass-spring effect. Moreover, the distinction between these two effects are explained in more detail by comparing the dissipated energy by each mechanism (viscous, thermal and structural effect).

Słowa kluczowe:
Meta-porous material, Biot-Allard poroelastic model, Mass-spring effect

Afiliacje autorów:
Ahsani S. - Katholieke Universiteit Leuven (BE)
Deckers E. - Katholieke Universiteit Leuven (BE)
Zieliński T.G. - IPPT PAN
Jankowski Ł. - IPPT PAN
Claeys C. - Katholieke Universiteit Leuven (BE)
Desmet W. - Katholieke Universiteit Leuven (BE)

Kategoria A Plus

IPPT PAN

logo ippt            ul. Pawińskiego 5B, 02-106 Warszawa
  +48 22 826 12 81 (centrala)
  +48 22 826 98 15
 

Znajdź nas

mapka
© Instytut Podstawowych Problemów Techniki Polskiej Akademii Nauk 2021