Experimental investigation on displacement amplification mechanism of steel wire rope-pulley damping systems with viscous damper

Abstract

In this study, a new displacement amplification damping system was proposed for maximizing the performance of a damping device, even in a stiff structural system. The proposed damping system comprises steel wire ropes, pulleys, and a viscous damper; the damper displacement is amplified on the basis of the working principle of a block and tackle system. Full-scale experiments were conducted to investigate the operating mechanism of the proposed damping system and evaluate its performance. The test results demonstrated that, when compared to the amplification efficiency of the theoretically expected value, that of the proposed system was reduced by 10–25% owing to elastic deformation of the steel wire ropes and a lag in pulley operation due to friction between the pulleys and pins. However, the magnification factors (ratio of damper displacement to interstory drift of frame) measured during the pulley operation were almost equal to the theoretical values; a maximum value of 5.77 was confirmed. Despite the lag in the pulley operation, the maximum operating velocity of the damper rod was almost the same as the theoretically predicted value. A velocity-dependent damping device was used in the experiments; thereby, the damper force corresponding to the maximum velocity was developed and amplified by the theoretical magnification factor. Ultimately, this contributed to the lateral force resistance of the frame for the proposed system.