Application of pre-stressed SMA-based tuned mass damper to a timber floor system

Shape memory alloy (SMA) is becoming a popularly studied smart material in the field of structural control. The feasibility of utilising an SMA in a tuneable mass damper to reduce the excessive vibration of a timber floor system was revealed in a pilot study. However, the in-service excitations on a floor can be complex and involve more frequencies and randomness; therefore, this paper aims to assess the effectiveness of the SMA-based semi-active TMD in a real-scale timber floor, where the free vibration and human footfall-induced vibration are considered as inputs. This study is conducted using numerical simulations on OPENSEES. By reducing the floor vibration at a range of frequencies, both cooling and heating the SMA are effective in retuning the off-tuned TMD and reducing the structural response. Footfall excitation involves more than one excitation frequencies, and the higher dominant frequencies can resonate with the off-tuning frequencies, increasing the structural response. Simulation results demonstrate that retuning using SMAs can effectively lower the structural response at a wide range of frequencies, thus attenuating the footfall-induced vibration.