Wave energy converter-inspired ultra-low-frequency double-mass pendulum damper for vibration control of offshore wind turbines

Abstract

The simple pendulum tuned mass damper (SPTMD) often requires impractically long pendulum lengths to achieve optimal vibration control of low-frequency structures, thus demanding significant installation space. Inspired by the emerging double-mass pendulum (DMP) oscillators in wave energy converters (WECs), this study, for the first time, explores the feasibility of using a DMP damper (DMPD) for low-frequency vibration control with enhanced spatial efficiency. The analytical optimal DMPD design parameters are derived. In addition to frequency tuning and damping ratios, the pendulum length ratio influences the control capacity. The DMPD control effectiveness is validated through a numerical case study of offshore wind turbines (OWTs) under wind-wave loads. In OWT applications, the DMPD realizes a control performance comparable to that of an SPTMD but offers higher spatial efficiency with 19 % (or higher) less installation space, thereby reinforcing its feasibility for installation within the OWT nacelle. Practical justifications for the use of the DMPD are also discussed. The trade-off between the control capacity and spatial efficiency of this device necessitates a careful design based on specific space constraints. Despite potential detuning issues, the original design of the DMP oscillator for WECs offers frequency and damping tunability. The results demonstrate the DMPD's promise as an alternative tuned-type vibration control device for low-frequency structures, particularly those with limited installation space (such as OWTs).