DOUBLE-PANEL NOISE BARRIERS WITH SEMI-ACTIVE COMPONENTS

Double-panel noise barriers provide significantly higher passive transmission loss compared to equivalent single-panel structures. However, their acoustic performance deteriorates rapidly at low frequencies due to low order structural-acoustic resonances. These resonances can be mitigated, for example, by active control systems. But when the availability of high-performance processors and energy sources is limited, it is worth considering alternative solutions, including semi-active methods. This paper investigates a semi-active control approach utilizing two types of semi-active components. First is a semi-active bistable link mounted between the panels, which are structurally coupled, when the link is turned on, or decoupled, when turned off. Second type is a semi-active element with a tunable mass moment of inertia, attached only to one of the panels. This element allows significantly altering the mechanical properties of the barrier. Both components complement each other. As a result, the components allows the noise barrier to adapt to noise with varying characteristics by altering its mechanical properties. The presented simulations shows that the proposed semi-active system can significantly enhance double-panel noise barrier transmission loss.