A Novel Passive-Self-Tuning Energy Harvester

To capture the maximum induced vibrational energy, it iscrucial to have near-resonance vibrations in an energyharvester. This can be accomplished by passive self-tuningresonators which can adapt themselves to the excitationfrequency. However, the existing self-tuning beamresonators can only, due to the gravity field, operate whenthey are placed horizontally, which makes it impossible tobe used in mobile electronic devices. In this paper, weintroduce a novel concept of beam resonators that is neutralto any orientation with respect to the gravity field and, thus,can be employed in mobile electronic devices. In this study,the influence of preload on the modal behavior is alsoanalytically and numerically investigated. Finally, with theaid of a nonlinear finite element simulation, we proposeusing preload in order to further optimize the performanceof self-tuning beam resonators.