Passive Self-tuning Resonance of a Beam with a Movable Proof Mass

Abstract

When a structure with a movable additional mass is periodically excited, the additional mass moves due to the vibration of the structure. As a result, the system can resonate by changing the natural frequency of a certain natural vibration mode including the added mass so that it approaches the excitation frequency. This phenomenon, called passive self-tuning resonance, is expected to be applied to the field of energy harvesting by vibration in terms of broadening the resonance frequency of the system. In this study, a simple system consisting of a beam and a slider was used to observe the dynamic behavior of the system by experiments and its characteristics were investigated. Experimental results show that, once the slider moves toward the antinode of one vibration mode of the system, and that mode resonates, the dominant mode eventually switches to another mode, and the slider moves to the antinode of that mode, and this series of movements is repeated. Numerical integration based on theoretical study gives results similar to the above experimental results, showing nonlinear coupling between the slider and the beam's multiple vibration modes.