SEMI-ACTIVE CONTROL OF NONSTATIONARY NOISE TRANSMITTED THROUGH STRUCTURES

Device noise is a serious problem in industry and at home. It impedes voice communication, prevents effective rest, but also poses a threat to hearing and reduces safety. Passive attenuation is often inadequate due to the low-frequency nature of such noise and the need to dissipate heat. Active methods for many applications are too complex, requiring multiple sound sources or actuators, which also involves significant energy consumption. Semi-active methods are an interesting alternative. The authors initially investigated the feasibility of using semi-active methods to reduce noise passing through panels and enclosures. They also designed new semi-active element. It involves repositioning additional mass in relation to the panel, which can significantly change the response of such a wall. With such a element at disposal, it is possible to choose and set it optimally for a given noise. An interesting challenge is the ongoing reconfiguration and optimization for non-stationary noise, such as that generated by an automatic washing machine. The aim of this paper is to propose a switching algorithm and analyze the effects of reducing non-stationary noise passing through the walls, using the developed semi-active elements.