Complex dynamics and targeted energy transfer of double-beam nonlinear energy sink with magnetic interactions

Abstract

Nonlinear energy sinks (NESs) have garnered sustained attention in recent years as highly efficient broadband vibration suppression devices. However, achieving optimal vibration control within limited space through the design of compact NESs configurations remains a key issue hindering its engineering applications. To address this, the present paper proposes a novel compact double-beam nonlinear energy sink device with magnetic interactions. The device constructs a two-degree-of-freedom vibration unit by cutting an internal sub-beam within the main beam, and integrates magnet mass blocks at the ends of the inner and outer beams. It utilizes the magnetic repulsion effect to develop an adjustable nonlinear stiffness system. The dynamic model of the 3DOF coupled system is formulated using Lagrangian method, with approximate analytical solutions derived through the harmonic balance method. The study conducts a parameter sensitivity analysis to explore the impact of NES parameters on the frequency response characteristics and vibration suppression performance of the primary system. Finally, the transient vibration suppression performance of various damping devices under various initial energy excitations is assessed based on critical performance indicators, such as the energy dissipation ratio. The findings show that the proposed NES achieves remarkable energy dissipation efficiency and robust performance across a wide frequency excitation range. This research presents a novel solution and theoretical foundation for broadband vibration control in engineering structures.