On panel vibration damping due to structural joints.

Abstract

Experimental results are summarized which show what effects various panel, joint, and ambient air parameters have on the damping of panel vibrations which is provided by joints connecting panels to stiffeners or other panels. From these results it is concluded that the dissipation of vibratory energy at structurally acceptable multipoint-fastened (riveted, bolted, or spot-welded) joints, at frequencies considerably higher than the panel fundamental, is primarily caused by the pumping of air produced as adjacent surfaces between fasteners move away from and toward each other. A method for estimating the damping of built-up panel structures is suggested, based on the concept of the absorption coefficient of a panel discontinuity and on empirical correlations of experimental data.