Damping of Vibrations of Clamped Flat Plates

The results of damping experiments for flat, square plates vibrating in air and in vacuum are preported. The data include measured dampining for plates of several materials and thicknesses, excited to resonance in each of a number of different modes. Two types of material damping and acoustic radiation damping to the air were included in equations of motion for plate vibration, and approximate solutions obtained for comparison with experiment. Agreement between these theoretical predictions and measured damping was poor. Although differences in measured and predicted material damping can possibly be attributed to energy losses in the plate clamping arrangement, similar differences in air damping cannot be easily explained. (Author)