Design and analysis of a collocated periodic vibration absorber-harvester

A collocated periodic vibration absorber-harvester (PVAH) is designed and the interaction between its absorption ability and harvesting capability is investigated. The PVAH consists of dual cantilever beams interconnected by a discrete spring. For energy harvesting purpose, both cantilever beams are partially covered with PZT layers. If the PVAH is properly designed, it could absorb vibrations in integer multiples of the base excitation frequency and harvest the vibration energy simultaneously. The PVAH can be designed based on its open or closed circuit state. To understand the performance of the PVAH, absorption and harvesting indicators are respectively defined and their dependencies on system parameter such as load resistance are examined. Numerical and experimental results show that PVAH outperforms a tonal dynamic vibration absorber when the excitation is periodic. In addition, experimental measurements reveal that there exists a best load resistance for maximum harvesting which depends on PZT coverage ratio. An illustrative PVAH case shows that the absorption performance diminishes 8.7% at maximum power harvesting when 15% of the beam length is covered with PZT layer. Experimental investigations conducted not only verify the theoretical calculations but also prove that collocated absorber and harvester design is feasible. Finally, a reasonable range of load resistance for the PVAH design is located and provided. This could be helpful to the vibration engineers for collocated absorber-harvester design.