Passive damping of large space structures

Abstract

The complex stiffness matrix and the mass matrix of a uniaxial bar subjected to constrained layer damping over its entire length are derived exactly by solving the differential equations of motion of the three-layered structure. The stiffness and mass matrices of a bar with segmented damping treatments are obtained by assembling the corresponding matrices for each segment and eliminating the internal nodes using a reduction procedure similar to static condensation. The natural frequencies, mode shapes, and loss factor of a pinconnected truss containing several damped members are computed by three different methods: truss finite element (TFE) method (exact), equivalent beam element (EBE) method, and scaled beam element (SEE) method, each method being more efficient than the preceding one. A 10-bay plane truss is considered as an example to illustrate each method. The EBE method yields very good results, but the savings in computation is not significant. The SBE method reduces the computational effort drastically and gives reasonably approximate results.

Estimation of Elastic and Damping Characteristics of Viscoelastically Constrained Carbon Strands

“…They also presented a method for the analysis of damped structural systems in which the structural components are represented by impedance models and analysed in frequency domain [15]. Sankar and Deshpande [16] developed a series of analytical and numerical techniques for the analysis of large space structures subjected to constrained layer damping. They determined the natural frequencies, mode shapes and loss factors of a pin connected truss containing several damped members by three different methods namely truss finite element method, equivalent beam element, and scaled beam element method.…”