Experimental Validation of Two Approaches Adopted for Examining Harvesting Energy from Rotary Magnetic Plucking Dynamics

• Main Authors: Yu-Jen Hsiao, 蕭又仁
• Other Authors: 舒貽忠
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/mtuazd

碩士 === 國立臺灣大學 === 應用力學研究所 === 107 === The thesis presents an experimental validation of two different theories adopted for examining harvesting energy from rotary magnetic plucking dynamics. The energy harvester device includes a piezoelectric bimorph mounted on a stationary base with a magnet attached to its free end. Energy is harvested by vibration of beam induced by non-contact rotary magnetic plucking. Assuming small tip displacement, the first theory estimating the harvested power is based on the fundamental mode of the magnetic interaction force applied to the resonant modal formulations of vibration. Instead, the second theory chooses the original form of the magnetic interaction force as the driving force to the resonant modal formulation of vibration. Two kinds of experimental setup are prepared for validating these two approaches. The first one chooses varying the distance of two magnets while keeping the radius of revolution fixed. The second one chooses varying the radius of revolution while keeping the distance of two magnets fixed. The results show that the first theory agrees quite well with the experimental rotary frequency response no matter what setups are prepared. However, the predictions based on the second theory are found in agreement with experimental observations only in the first setup with larger ratio of magnetic distance to the radius of revolution. In addition, there are significant deviations between theory and experiment for the second setup where the radius of revolution is changed under the fixed distance between two magnets. An explanation for such discrepancies is that the impulsive force containing infinite modes may not be suitable to be directly applied to the resonant model formulation of vibration.