Experimental verification of electromagnetic multiple tuned mass dampers for energy harvesting and structural control

This paper proposes electromagnetic (EM) multiple tuned mass dampers (MTMDs), hereafter referred to as EM‐MTMD system, for decreasing the vibration responses of high‐rise buildings under earthquake excitations. The EM damper substitutes the traditional fluid damper, enabling the proposed system to convert each TMD unit's vibration energy into electrical energy that can be harvested. Moreover, the system applies a rotary EM damper to ensure the energy dissipation device achieves a long stroke. Each TMD's damping coefficient can be easily adjusted without changing the EM damper configuration. We established a mathematical model of the EM‐MTMD system and derived its theoretical formula. Subsequently, we developed an optimal design method that considers inertance of EM damper for the EM‐MTMD system. For verifying the vibration control performance of the EM‐MTMD system, a model structure with long vibration period (3.53 s) and weight of 6 tons was manufactured to simulate the fundamental modal vibration of a 38‐story building. A prototype three‐unit EM‐MTMD system with a total mass ratio of 2% of the model structure was then designed and implemented to verify the system's dual functions of energy harvesting and vibration control. In shaking table tests, the EM‐MTMD system components were tested first; the model structure was then combined with the EM‐MTMD system and tested extensively to demonstrate the system's effectiveness in controlling the building structure's vibration and generating electrical energy under earthquake excitations. The test results indicated that the EM‐MTMD system can simultaneously decrease building responses effectively under real earthquake excitations and generate power.