Multi-parameter pendulum tuned particle damper for vibration suppression in offshore wind turbine towers

To address the challenge of suppressing low-frequency vibrations in offshore wind turbine towers under complex environmental loads, this paper innovatively proposes a pendulum-tuned particle damper (PTPD). This design combines the high space utilization efficiency of pendulum structures with the broadband energy dissipation advantages of particle damping. A four-degree-of-freedom coupled tower-PTPD model and its Lagrangian equations of motion were established. Using the Finite Element-Discrete Element (FEM-DEM) coupling method, the effects of pendulum length and particle diameter on vibration suppression performance were systematically studied under three wind load conditions. Simulation results show that under Condition 1, a PTPD with a 3.50 m pendulum length filled with 200 mm iron-based particles achieves a peak vibration reduction rate of 58.1%, significantly reducing the tower's vibration acceleration amplitude. A 1:65 scaled model was designed and tested, demonstrating that a combination of 625 mm pendulum length and 10 mm particles achieved a 58.0% vibration reduction rate. This validates the parameter optimization principles derived from simulations and provides an effective solution for anti-fatigue design of offshore wind turbines.