On the performances of a SMA-based tuned mass damper

Tuned Mass Dampers (TMD) have received special attention in the recent years due to their ability to reduce structural vibrations. In this work, some aspects related to the performances of a TMD based on pseudoelastic Shape Memory Alloys (SMA) are investigated. The response of such devices, besides the customary mass and stiffness ratios, also depend on the dissipative features of the hysteresis loops that can be obtained by means of such materials. The performances of the system are evaluated by the numerical computation of Frequency Response Curves and of the equivalent viscous damping. The results of the analyses show that the damping features of the system are strongly frequency and amplitude-dependent. Moreover it turns out that a crucial issue in the realization of this device is the control of the forcing amplitude in order to avoid that the SMA oscillates with pseudoelastic loops bounded by a second elastic branch. At lower forcing levels, the TMD can effectively act as vibration damper based on the dominant hysteretic energy dissipation, whereas for higher forcing amplitudes its effectiveness is strongly limited by the large oscillations associated with the occurrence of jumps between solutions with different qualitative featur.