Design of a Two Degree-of-freedom Tuned Mass Damper for a Suspension Bridge Model

Resumo

Tuned Mass Dampers (TMDs) are very useful when one aims to mitigate vibration-related problems.

This device, once attached to a structure, considerably attenuates the effects of dynamic loads (e.g, wind and seis-
mic activities). Although TMDs exhibit a favorable performance over one specific frequency range, structures have

multiple natural frequencies, and sometimes this raises the necessity of attaching a different TMD for each one of
them. However, this kind of solution often overloads the primary structure and limits TMDs’ damping performance

(weight penalty). The purpose of this work is to design a TMD capable of damping two vibration modes of a sus-
pension bridge’s deck. For this, the primary structure is modeled by the Finite Element Method, using ANSYS®

combined with a MATLAB® routine, then it is conceived its modal and harmonic analysis, identified the targeting
modes, and applied the “Equal Peak Design” technique to estimate the TMD’s optimum damping and frequency
ratio. Based on those factors, it is determined the final TMD dimensions. The results shows the developed TMD
has the potential to significantly reduce deck’s vibration levels, for its parameters can be effectively tuned to realize
the target modes control.