Design and dynamic characterization of a large-scale eddy current damper with enhanced performance for vibration control. (November 2020)

• Record Type: Journal Article
• Authors: Zhang, H.Y.; Chen, Z.Q.; Hua, X.G.; Huang, Z.W.; Niu, H.W.
• Is Part Of: Mechanical systems and signal processing. Volume 145(2020)
• Publication Date: 2020-11
• Subjects: Vibration control -- Eddy current dampers -- Rotary dampers -- Damping density -- Force-speed characteristics -- Seismic control; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2020.106879
• Languages: English
• ISSNs: 0888-3270

Abstract

Highlights: Development of rotary eddy current dampers (ECD) with enhanced damping density. Dynamic characterization of rotary ECD using numerical and experimental approach at low and high speeds. Achievement of a damping density as high as fluid viscous dampers for rotary ECD. Nonlinear and limiting feature of force-speed curve of rotary ECD. Abstract: Eddy current dampers (ECD) are promising devices for vibration control of dynamic systems, but their application in civil structures is very limited due to a low damping density. This study describes the development and dynamic characterization of a large-scale rotary ECD with enhanced performance for structural applications. The rotary ECD consists of a conductive rotor, a stator with permanent magnets, and a set of ball screw which converts the linear motions across the damper into rotations of rotor. The torque at different rotating speeds is evaluated by using a 2-D analytical method considering the reaction magnetic field caused by eddy currents. Laboratory experiments are conducted to validate the numerical results obtained for a simple eddy current torque generator and a large-scale ECD. It is shown that the analytical model agrees with nonlinear finite-element simulations, but is higher than the test results. The large-scale rotary ECD achieves a high damping density up to 24.9 MN·s/m 4 at a low speed. Moreover, the damping force of rotary ECD is highly nonlinear and self-limiting as a function of rotating speeds; it first increases with speeds and after reaching a maximum at a critical speed it decreases for higher speeds. Numerical simulation on seismic control of a SDOF system and a 5-DOF system showed that the rotary ECD performs as well as the fluid viscous dampers having the same secant damping coefficients. Finally, effects of changing design parameters on force-speed curve are studied in details.