Analytical and experimental investigation of a motion amplified rotational friction damper

Abstract

This article introduces a novel rotational friction damper to enhance energy dissipation capacity of structures. The proposed damper contributes to force and energy dissipation capacities by utilizing friction torques between steel plates and aluminum pads (disks) that rotate relative to each other. The novelty of the damper stems from the motion amplification mechanism, which is achieved by the small initial angle between the structural element and the steel plate arms of the damper. Furthermore, friction damping occurs in all joints of the mechanism as opposed to solely at the middle joint, which is the case for the existing friction dampers that are placed at beam-column joint regions. The proposed damper is compact and particularly effective for joints where small gap openings occur, such as precast post-tensioned structural systems. The amplification mechanism is specifically designed to magnify the rotations due to this gap opening. Experiments, conducted on the damper with varying parameters, show that proposed damper’s performance is very satisfactory in terms of both force and energy dissipation capacities.