Bilateral-Plate Eddy Current Damping: Paradigm Shift for Enhancing Energy Dissipation in Vibration Control

Abstract

Eddy current damping is widely applied in scenarios where high speeds or low damping are involved. However, due to its low energy dissipation density in traditional configurations, there has been a long-standing bottleneck of low vibration damping efficiency, especially for civil engineering applications with low vibration frequencies and low velocities. Since the invention of the new unilateral-plate eddy current damper (UP-ECD) where single-sided permanent magnets and a single-sided conductor plate are respectively fixed on two objects moving relative to each other, significant improvements in energy dissipation density have been achieved by adding back irons behind the permanent magnets and the conductor plate. Building upon this, the present study further improves the eddy current damping generation unit by proposing a new bilateral-plate eddy current damper (BP-ECD). The proposed BP-ECD features rectangular permanent magnets with alternating magnetic poles in the center, corresponding to two conductor plates on both sides, with back iron behind each conductor plate. This study develops the new eddy current damper and characterizes its damping characteristics through theoretical analysis and experimental testing. The proposed BP-ECD can increase the damping coefficient to 1.66 times compared to the UP-ECD at an air-gap thickness of 5 mm. The accuracy of the theoretical analysis results is compared with finite-element analysis results regarding flux density distributions and damping coefficients. Through parameter analysis, the applicability range of linear damping assumption in the analytical model is examined, and the influence of different parameters on damping coefficient is analyzed. Finally, through testing the prototype damper installed on a steel frame, the accuracy of the analytical model and finite-element model is verified. The proposed BP-ECD undoubtedly holds great potential in substantially enhancing the energy dissipation density of various eddy current dampers, thus opening up broad and promising prospects for numerous applications.