Evaluation of multiple active lever-type tuned mass dampers for structures under ground acceleration

The multiple active lever-type tuned mass dampers (MALTTMD), consisting of many active lever-type tuned mass dampers (ALTTMDs), is proposed in this paper to gain a control system with high robustness and effectiveness, in which the static and dynamic stretching of the spring may be freely adjusted. The main objective of the present study is to evaluate the control performance of the MALTTMD (including the MALTTMD stroke). The evaluation of the MALTTMD is performed in terms of both minimizing the maximum dynamic magnification factors of the structure and the maximum dynamic magnification factor of every ALTTMD in the MALTTMD. The results indicate that the MALTTMD with the actuator set at the mass block can render better effectiveness and higher robustness compared to the MALTTMD with the actuator set at other locations and also has higher effectiveness than a single ALTTMD with equal total mass ratio and normalized acceleration feedback gain factor (NAFGF). More importantly, the static and dynamic stretching of the spring in the MALTTMD with the actuator set at the mass block may be freely adjusted in accordance with the practical requirements through changing the mass block location, while approximately maintaining the same control performance as the AMTMD. Additionally, a parametric study is carried out to examine the effect of the dominant ground frequency ratio (DGFR) on designing the MALTTMD.