Active noise control of a mechanically linked double panel system coupled with an acoustic enclosure

Active control of sound transmission through a mechanically linked double-wall structure into an acoustic enclosure is investigated in this paper. Based on a fully coupled vibro-acoustic model, the effect of mechanical links on the selection of control strategies is studied by examining (a) cavity control using acoustic sources inside the air gap and (b) structural control using structural actuators between the two panels. The relationship between the transmission path and the control strategies is explored. Numerical results show that cavity control can provide good noise attenuation for soft links when acoustic transmitting path dominates, while either structural or cavity controls can be used with the increase of stiffness of links depending on the frequency range of interest. For each case, the dominant control mechanism is examined and the alteration in the structural–acoustic coupling is analyzed to explain the mechanisms of attenuation. The effect of the acoustic mode (0,0,0) on active control of energy transmission is also discussed, giving guidance to choosing the appropriate control arrangement to ensure the maximum control performance.