A novel rotational inertia damper for amplifying fluid resistance: Experiment and mechanical model

Abstract

An inerter is a two-terminal mechanical device with the property of generating a resisting force that is proportional to the relative acceleration across its terminals. Due to its distinct mass amplification and negative stiffness effects, inerter has been applied to enhance the performance of conventional control systems, e.g. tuned mass damper (TMD) and vibration isolation system (VIS). Very recently, a novel inerter-based damper dubbed rotational inertia damper (RID) that is capable of generating a significant damping force was proposed by the authors to control the vibrations of offshore platforms, and its control effectiveness was examined through analytical studies. In the present study, a RID prototype was manufactured and tested under harmonic excitations for an in-depth understanding and demonstration of its mechanical behaviors. A precise mechanical model considering inerter nonlinearities is proposed to predict the behaviors of the RID, and the corresponding parameters are identified by using a nonlinear least squares method based on the experimental results. The theoretical results predicted by the proposed mechanical model are then compared with the experimental results, good agreements are achieved. The results demonstrate that the developed RID has a good capacity for energy dissipation, and the proposed mechanical model is accurate in predicting the behaviors of the RID.