Precise and efficient computation of complex structures with TMD devices

Proportionally damped structures give non-proportionally damped mathematica l models when tuned mass damper (TMD) devices and/or viscous dampers are in stalled. The precise analysis of unwanted enforced vibration of such a comb ined system, i.e., of the structure plus the TMD devices and/or dampers, is very cumbersome and inefficient for structures with many (e.g., 10(3)-10(5 )) degrees of freedom. This short paper gives a convenient and efficient me thod for computing the results for such problems which involves only the fi rst few undamped modes of the structure and is not iterative. Results are g iven for a simple illustrative truss and for an actual offshore jacket plat form. (C) 1999 Academic Press.