The Radiation Efficiency of a Plate Carrying Concentrated Masses

抄録

The acoustic radiation efficiency of a plate carrying concentrated masses has been studied. The variation of the radiation efficiency of a plate occurs due to attaching masses to the plate at frequency range below the coincidence frequency. The reason for the efficiency variation can be interpreted physically by using the conception of volume velocity cancellations. The volume velocities on the plate surface except in the regions near the four corners are canceled out when the plate is uniform, whereas the cancellation of the volume velocities is disturbed around the mass attached on the plate. Attaching a mass increases the radiation efficiency of a plate. In this paper, the approximate expression has been developed for the variation of the radiation efficiency of a plate due to attaching concentrated masses in the case where a large number of modes are excited. Experimental results show that the approximate expression is valid and useful.