抄録
Located in a dynamic ocean environment, offshore platforms are inevitably affected by external forces, tuned mass damper (TMD) for damped linear structures has attracted considerable attention in recent years; however, linear dampers are effective only for a single resonance frequency, providing effective suppression only within a very narrow frequency band. In this study the effectiveness of the nonlinear TMD for vibration control of a seismically-excited offshore platform structure is evaluated. An experimental model of the offshore platform with the nonlinear TMD is developed. The nonlinear TMD device has a single-mass block with two pairs of permanent magnets, and the repulsive force between the permanent magnets is produced by a variable-stiffness spring, providing the damper with a wide operational frequency range. This paper involves experimental and analytical investigations that comprehensively extend the understanding of the wide frequency range performance and damping characteristics of a magnetic nonlinear TMD system under two strong seismic vibrations.
