1. Key Laboratory for Wind and Bridge Engineering of Hunan Province, Hunan University, Changsha 410082, China；
2. Vibration and Shock Technology Research Center, Hunan University, Changsha 410082, China
Abstract：The ball screw type eddy current damper (BS-ECD) is a novel velocity-based nonlinear. In this paper, the formula of energy dissipation and equivalent damping ratio of BS-ECD were derived at the first. Then, the characteristics of the damping force-velocity curve and hysteresis curve were analyzed, based on which the displacement magnification factor, the transmissibility, and the peak damping force were calculated to evaluate the BS-ECD’s control performance via a single-degree-of-freedom structure under harmonic excitations. Finally, the performances of BS-ECD were compared with those of the nonlinear fluid viscous damper (NFVD). The results indicate that the nonlinearity in the damping force-velocity curve becomes stronger as the BS-ECD’s critical velocity decreases, and an optimal critical velocity can be obtained to minimize the peak of the damping force under the condition in which the damper’s energy dissipation remains unchanged in each cycles. Under the design principle of the same equivalent resonant damping ratio, the BS-ECD with a dimensionless critical velocity of 0.8 performs better than NFVD with a velocity index of 0.3 in respect of the vibration reduction and isolation performance.
