Abstract

The sound absorbing means are based on a resonance membrane formed by a layer of polymeric nanofibers, which is restricted by a frame. The resonance membrane is then, upon impact of sound waves, brought into forced vibrations, whereby the kinetic energy of the membrane is converted into thermal energy by friction of individual nanofibers, by the friction of the membrane with ambient air and possibly with other layers of material arranged in its proximity. Moreover, part of the kinetic energy of the membrane is transmitted to the frame, to which the membrane is securely attached, and other part is converted into thermal energy due to increased friction in its inner structure, which is caused by the fact that the neighboring parts of the membrane, separated at least partially by the frame or its elements, may vibrate with mutually different periods and/or deviations. The frame is formed by a mesh of grid that can be regular in order to obtain uniform properties over the whole area of the sound absorbing material. The size and shape of the mesh affect the sound absorption or more precisely resonance behavior of the means. To obtain desired sound absorbing characteristics, the resonance membrane is connected to the frame with positive, zero, or negative tension.

Keywords: nanofibers, membrane, resonator, sound absorption, frame
