Wave Propagation on Beam-Plate Systems

Abstract

Formulas for the attenuation of bending waves that travel over a beam-plate system, containing one or several beams, are derived and compared with measurements. It is found that one beam gives an attenuation which is very small near the resonances of the beam and rather high elsewhere, but in the average over wide frequency bands the attenuation appears to go nearly like the square root of frequency. The addition of beams of the same material and dimensions does not give an appreciable increase in attenuation. Formulas for the force impedance and mean-square velocity of beam-plate systems are also given. Finally, the damping of a beam by a plate attached to it is discussed.