Dynamic analysis of a tunable electromagnetic bistable system

Abstract

Bistable structures exhibit a unique snap-through behaviour, which is widely used in different engineering disciplines. Some bistable systems have the ability to change dynamic characteristics such as the depth of the potential wells, distribution of the stable equilibrium points, and symmetry of the potential function, but only for the initial assembly. Therefore, this study presents a novel tunable electromagnetic bistable system (EBS), which can be adjusted online. An EBS is composed of a mechanical spring and an electromagnetic negative-stiffness unit in parallel. To characterise such a system, a static model was developed using the filament method, and the dynamic response was calculated using the harmonic balance method to better understand the EBS tunability. We conducted a series of studies aimed at revealing the effects of the geometric parameters, initial conditions, and excitation level on the dynamic characteristics. Finally, a switch between the interwell and intrawell oscillations of the actively tunable EBS was experimentally demonstrated, improving applications such as adaptive energy harvesting and active vibration control.