DAMPING IN STRUCTURES - ITS EVALUATION AND TREATMENT OF UNCERTAINTY

This paper concerns the damping in structures with emphasis on treatme nt of inherent uncertainty in its prediction and estimation, Material or structural damping is addressed as well as damping due to the aerod ynamic and hydrodynamic forces of the fluid surrounding the structure. The reported data base on damping information is examined in light of wind sensitive structures that rely heavily on damping for their perf ormance under winds. The basic techniques for estimation of damping fr om response time histories are reviewed, and the random decrement tech nique is considered in some detail. The implications of the uncertaint y of damping on system response are analyzed in terms of a perturbatio n technique, second-moment analysis and Monte Carlo simulation Several simple illustrative examples are provided throughout the text.