Establishment of the evaluation standard and the analysis technique for the tip mass method in piezoelectric energy - harvesting systems

Two models were developed a pre-stress model and a no-pre-stress model for considering the effects of a tip mass with and without pre-stress induced by gravity, respectively. Three tip masses - 6, 18, and 30 g - were used in experiments, and four cases were considered: the above three tip masses and a 0 g case, corresponding to no tip mass. Two prominent effects of the tip mass were theoretically predicted and experimentally verified. We established an evaluation standard and an analysis technique for efficiently analyzing these two effects of the tip mass on the output power of a piezoelectric energy-harvesting system. For both models, a higher output power was obtained in a system with a tip mass than in a system without a tip mass. Results of the experiments and of a critical voltage analysis demonstrated that the developed tip mass method successfully augmented the output power of the system.