OPTIMIZING NOISE ABSORPTION THROUGH HYBRID ACOUSTIC BRICKS: NUMERICAL SENSITIVITY ANALYSIS OF THE ACTIVE VIBRATION CONTROL LOGIC

Hybrid acoustic absorber have been implemented in order to overcome the limitations of common acoustic panel used for the control of room acoustics parameters. Indeed, the hybrid system allows to enhance the acoustic absorption in a wider frequency range. In this research frame, a hybrid absorber block has been developed by combining active Structural Acoustic Control (ASAC) and high frequencies Passive Noise Control (PNC). This innovative smart structure, made of 3D-printed blocks, offers an easy-to- mount and customizable solution. It has potential applications in many fields, such as architecture, engineering and construction industry, where noise is generated by broadband sound sources. The passive destructive interference proved to be an effective solution for high frequencies, where the wavelengths of interest are quite small, but it is difficult to be implemented at low frequencies and where space is limited. This paper focuses on the sensitivity analysis of the parameters of the active contribution. It is here implemented through a 5mm thick aluminum plate actuated by a piezoelectric patch. Mathematical modeling and tests with the Kundt tube demonstrate that the proposed approach can increase the average absorption coefficient in normal incidence condition by more than 80%, in the 125-1000 Hz frequency range.