Measurements and calculations of the sound attenuation by a phononic band gap structure suitable for an insulating partition application

We report a strong attenuation of sound waves in a phononic band gap crystal of steel rods arranged in air. We investigate the attenuation level reached in the gaps for finite thickness samples. We show that a bypassing of sound waves by the sides of the sample are responsible for the observed saturation of the attenuation level in the gaps. Beyond this effect, we demonstrate the improvement of the acoustic insulation performance brought about by the periodicity of the crystal in comparison with the so-called mass law. (C) 2003 American Institute of Physics.