Investigation and Modeling the Effect of Different Filler Materials on the Sound Absorption Properties of Double Base Persian Rugs

Rug is one of the cultural and artistic symbols of Iran, which is several thousand years old and is used as
an exquisite flooring or to decorate the interior of various places. Nevertheless, this art work has acoustic
properties due to the high volume of fibers and thickness. Therefore, in this paper, first a new structure
of the rug is introduced and then its acoustic properties are evaluated and modeled. The structure of
the new Double Base Persian rug is similar to the structure of a regular rug, and the only difference is
that there are two sets of warp yarns (instead of one) with a certain distance. In order to investigate the
effect of double bases and also the presence of various materials with different percentages in the gap
between the two bases on the sound absorption of the new rug, different samples were produced. It is
worth mentioning that the effect of the presence of pile on the sound absorption of the new rug has been
investigated. The sound absorption of the samples was measured using an impedance tube method and the
Johnson-Champoux-Allard model was used to model the sound absorption of the samples. The obtained
results showed that although the kind of filler material has a little effect on sound absorption, the sound
absorption increases by filling the gap between the two bases and by increasing the filling percentage.
The Johnson-Champoux-Allard model also indicated a very good agreement with the experimental data.