Experimental investigation on the hysteretic dynamics of a regenerative hybrid electrodynamic cable damper

Bridge stay cables that are constantly exposed to fluctuating wind environments are subject to constant or transient vibration, which hinders the serviceability and causes maintenance problems for the cables and dampers. A regenerative hybrid electrodynamic cable damper can semi-permanently reduce the vibration and generate electricity. This study proposes a regenerative hybrid electrodynamic cable damper that can be used as an alternative to existing dampers while reducing maintenance costs. Shaking-table experiments were performed on the proposed damper prototype to measure the dynamic hysteresis according to the excitation conditions and changes in damping characteristics and power generation according to external resistance. The hysteresis, damping force, dissipated energy, and damping coefficient changed non-linearly according to the excitation conditions and external resistance. Further, the maximum damping force, induced current, and power produced increased, compared with those of a coil-type electromagnetic damper. The experimental results confirmed that the proposed damper can be used in autonomous vibration control and monitoring system for stay cables because it possesses a versatile semi-active control characteristic that is achieved using a variable resistor and a self-generation function.