Proposal of optimum tuning of semiactive TMDs used to reduce harmonic vibrations based on phase control strategy

Abstract

Tuned mass dampers (TMDs) are a well-established technology for passive structural vibration control involving harmonic vibrations. Some design issues are critical to guarantee the proper functioning of the device, in particular, the adequate tuning and the adequate space to accommodate the TMD stroke. With regard to the first aspect, semiactive TMDs were proposed as an alternative means of correcting the vibrating frequency of the device by adding a semiactive element between the TMD and the structure. In this case, several control strategies have been proposed, among which phase control has proven to lead to excellent results. However, in the framework of this control approach, the minimization of the structure displacements is often used as the main objective of the control, as the relative displacements of the TMDs mass are considered a secondary issue, which nevertheless may be a crucial aspect in some applications. In this context, this paper proposes a strategy to optimally tune the semiactive TMD, taking into account a balance between the level of the reduction of the structural response and the amplitude of the TMD stroke. The optimal tuning is found by minimizing the system stationary mechanical energy. The problem is formulated as an optimization process, and the corresponding results are presented and discussed.