Adaptive tuned mass damper based on pre-stressable leaf-springs

Lightweight bridges exhibit a high live load to dead load ratio. Thus, their resonance frequencies depend on the current loading state and can vary in quite a broad range. This behavior is a real challenge in vibration mitigation of such structures controlled by tuned mass dampers (TMDs), since the performance of single passive TMDs degrades significantly if the resonance frequency of a structure differs even slightly from design frequency. This study proposes an adaptive TMD, which continuously adapts its natural frequency to the current resonance frequency of the structure. The concept is based on pre-stressable leaf-springs that are controlled by piezoceramic stack actuators. Experiments performed on a first prototype show that the TMD is continuously tunable in a broad frequency range.