Tuned Constrained Layer Damping Of A Cantilevered Plate

Abstract

A damping patch is shown to behave as a constrained layer damper (CLD) for the bending modes of a tapered cantilevered plate, while behaving as a tuned damper for the sway modes. This dual nature leads to higher damping capacity for the sway modes than would be otherwise possible using a similar coverage of conventional CLD, at the expense of optimum CLD performance in bending. An added variable end mass allows determination of the frequency dependence of experimentally measured loss factors and those calculated using a finite element model. Measured loss factor frequency dependence is compared with predictions from CLD theory and tuned damper theory. The plate response is measured using laser Doppler vibrometry for out-of-plane motion, and laser Doppler anemometry for in-plane motion, while force excitation is measured with a piezoelectric transducer. Modal analysis of measured mobility frequency response functions yields experimentally determined mode shapes, frequencies, and loss factors. A p-type finite element code, in conjunction with the modal strain energy method, is used to perform a normal modes and damping analysis of the damped plate geometry for comparison with experimental results.