Vibro-acoustic coupling response analysis and noise control of the window and cabin of aircraft by applying acoustic waveguide modal expansion method

摘要

A vibro-acoustic coupling model is established to investigate the sound transmission performance through the double-panel structure in convected fluids, aiming for analyzing the sound transmission performance through the windows of an aircraft into one's cabin. Also, a new technique based on acoustic waveguide modal is presented to study the vibro-acoustic coupling performance of the window and the aircraft cabin. In order to simplify the analysis, a double-beam with enclosure is employed. Some parameters, including incident angles, the velocity of convected flow, and the geometrical dimensions of the double panels, are analyzed. Studies have shown that the standing-wave resonance of the enclosure play a important role in the sound transmission of the double-beam with enclosure systems. With the increase of the thickness of the beam, the sound insulation performance of the structures is improved and the much more dips arise in the sound transmission loss (STL) curves. With the change of the length of the beam, the coupling relationship between the beam and the sound field has significant change. Air gap thickness, incident angles and Mach number change the sound insulation performance of structure, but the number and position in the dips of the STL curves have no significant change. The acoustic waveguide modal expansion method can reveal the vibro-acoustic coupling performance of the double-beam structure and cabin of airplane accurately. At last, the force control strategy of the noise control is also studied and indicates this control strategy is able to improve the sound insulation performance of the structure in the low frequency range.