First Numerical and Experimental Results on Active Controlled Glazed Facades

Both recent legislation codes and the evidence of the effects of high noise levels on human health have directed research activities towards the problem of the improvement of Sound Transmission Loss (STL) of glazed facades in the frequency range (low-medium) where passive means were already shown to be not effective. Adopting active control systems may help to cover the lower set of frequencies, where traffic and railway noise produces high level of disturbance. In this paper it is shown how Piezoelectric (PZT) stack actuators may be installed on large curtain walls, improving their STL. They are demonstrated to be particularly useful to avoid drops of STL in correspondence of resonance frequencies of windows, hence increasing their overall STL. Some simulations on the noise reduction obtained inside a standard building enclosure were performed, comparing the noise transmitted by a standard window with the corresponding active controlled one and several technologies for the installation of PZT actuators are suggested.