Wide-Band Random Vibration of Circular Plates

Abstract

When a uniform circular thin plate is excited at a point by a stationary wide-band random force process the transverse motion response at any point is also a wide-band random process. If enough modes are excited, however, there is an unexpectedly simple pattern in the spatial distribution of mean-square response. The main features of the pattern are narrow lanes of intensified response along the diameter through the driving point and along the circle, concentric with the plate boundary, which passes through the driving point. This phenomenon is investigated analytically and experimentally for a free-edged aluminum plate, 0.16 cm (1/16 in.) thick and 0.91 m (3 ft) in diameter. Qualitative agreement is obtained between measured response distributions and the predictions of an idealized analytical model for excitation bandwidths within the range from 500 to 5000 Hz.