Promising Methods for Reducing the Vibrations of Aircraft Structures under Acoustic Excitation

Tests for measuring the vibration characteristics of a typical fuselage panel of a regional aircraft, as well as the board, flap, and wing structures of a real aircraft with various vibration damping sets, have been carried out in reverberation chambers and on a full-scale testbench. Under the conditions of acoustic excitation for a model panel and real aircraft structures, the efficiency has been determined for the following vibration reducing means: the change of the boundary conditions and stiffness of frames, the lining of a structure with single-sided vibration-damping sandwiches and sheet vibration-absorbing materials VTP-1V and SKLG-6020M, and the use of stringer and frame simulators, including their combinations with dual-sided vibration damping sandwiches. It is shown that a significant decrease in structural vibrations can be attained within a broad range of frequencies by using a combination of different methods. At low frequencies, an effective tool is the conversion of long-wave frame vibration forms into shorter-wave ones. In the region of medium frequencies, structural vibrations can be efficiently reduced by single-sided sandwiches, as well as stringer simulators together with dual-sided sandwiches. In the region of high frequencies, the most effective means is the lining of a structure with sheet vibration-absorbing coatings.