Controle ativo de ruído aplicado a venezianas acústicas

Abstract

The development of new technologies for ventilated acoustic windows is within the context of the promotion of energy efficiency of buildings, including the compatibility of the dichotomy natural air conditioning and sound insulation of buildings. Traditionally, the use of passive methods for noise control in ventilated window has limited sound insulation at low frequencies, with transmission loss below 10 dB. Alternatively, techniques for active noise control have been applied, including yourself those naturally ventilated. However, the current state of this technology still has use restrictions for high frequencies. The use of hybrid methods is presented as a solution to the acoustic performance enhancement at low, medium and high frequencies. Given this perspective, the present work proposes the application of techniques for active noise control is applied to acoustic louvres. So, highlights the concept of active acoustic louvres, a hybrid technology that aims to increase the acoustic attenuation at low frequencies by incorporation of smart materials in the blades of the shutter, which are equipped with passive materials for sound absorption at higher frequencies. Thus, this paper presents a procedure for modeling the transmission loss of active acoustic louvers, using analytical and numerical methods associated with optimization techniques. The theoretical results suggest the feasibility of applying the techniques of active noise control in acoustic louvres, with weighted sound reduction index exceeding 35 dB and a maximum power requirement of less than 15 W.