A Novel Passive Mechanism to Improve Induced Strain in Two-DOF Piezoelectric Energy Harvester

Sensors have a significant role in Structural Health Monitoring and have limited operation life due to the limited life of batteries. Vibration-based cantilevered piezoelectric energy harvester is to be improved in their performance to satisfy the power requirements of remote sensors with existing limited host structure vibrations. This work focuses on increasing the strain induced in harvester beam by enhancing the amplitude of vibrations at root of cantilevered piezoelectric harvester beam by attaching four-bar mechanism with spring as dynamic magnifier. As output voltage from piezoelectric material depends on strain induced in it, strain gauges are pasted on harvester beam instead of piezoelectric patch and strain gauge results are discussed. Experimental results show that for a given input base displacement, four-bar mechanism improved strain in harvester beam in first mode by 1.5 times and in second mode it approached as that with cantilevered harvester and exhibits wider operational bandwidth when compared with conventional cantilevered energy harvester.