Tuned mass dampers incorporating wire rope springs

The effectiveness of wire rope spring tuned mass dampers (TMDs) in suppressing across wind structure oscillations was examined through testing of an aeroelastic model of a slender tower equipped with this type of TMD. The response reduction achieved by adding the TMD was considerable and was quantitatively expressed in terms of an equivalent viscous damping. A comparison was made between the non-linear TMD and an equivalent optimized linear TMD.; The equations of motion were derived for a translational single-degree of freedom system equipped with a "pendulum-type" TMD under dynamic force and base acceleration excitations. The complex frequency response functions were obtained, from which the optimum tuning parameters of the TMD under random white noise excitations were determined. The effects of both the inherent structural damping and the aerodynamic damping on the optimum tuning parameters were studied and simplified charts to account for such effects are provided.; An extensive experimental study of wire rope spring TMD's is presented. A single-degree of freedom system with a "pendulum-type" wire rope spring TMD was tested on a shaker table. The test program included two mass ratios, single and double-sided spring arrangements, two wire rope diameters, three spring attachment positions and four excitation levels. The system was tested under a Gaussian random white noise base acceleration. Based on areas under the mechanical admittance functions, TMD response parameters were evaluated. Moreover, those parameters were compared to those of an optimized linear TMD.; Design charts for wire rope spring TMD were developed. The probability distribution of structure-TMD relative displacement envelope was assumed to be of the Rayleigh-type and was used as a weighting function in averaging the amplitude-dependent responses. Contour plots for the equivalent viscous damping ratio, provided by the TMD, and the ratio of root-mean-square (RMS) relative displacement to RMS primary system displacement are presented. Both the equivalent viscous damping ratio and the RMS displacement ratio are functions of the mass ratio of auxiliary to primary system and the normalized RMS relative displacement. The use of the design charts is demonstrated by an example. (Abstract shortened by UMI.)...