DEVELOPMENT AND EXPERIMENTAL VERIFICATION OF DAMPING ENHANCEMENT METHODOLOGIES FOR SPACE STRUCTURES by

A frequency domain system modelling technique is developed for mechanical systems. The technique is derived from Tellegen's Theorem for electrical networks and is applied to discrete mechanical systems. The elements are modelled in terms of their mechanical impedances. A global system model is assembled from the constitutive impedances. The global system model is used to determine the model exact pole locations and system energy dissipation and storage properties. An approximate method for finding modal frequencies and loss factors using the system impedance matrix and assumed modeshapes is developed. This method reduces to Rayleigh's Quotient in the case of an undamped system. Impedance models for several damping enhancement mechanisms are presented. Among these are models for viscoelastic materials, the classical proof mass damper, and a new damping enhancement concept called the shunted piezoelectric. The shunted piezoelectric damping mechanism i