Theoretical Model and Performance Tests of Rotational Eddy Current Dampers with Cable

A novel rotational eddy current damper with cable is proposed, which is composed of inerter, spring and damping elements. In order to validate the mechanism for vibration mitigation, a mechanical model of a single-layer frame equipped with the damper is built. A series of vibration tests are carried out in terms of the frame, inerter and eddy current damper to analyze the impacts of air gap dimension between the conductor plate and permanent magnet, the material and thickness of the conductor plate on additional damping ratio. The conductor plates used in the tests include copper plates with the thickness of 5 mm or 10 mm, iron plate with the thickness of 5 mm, and a composite plate made up of a 5 mm thick copper plate and a 5 mm thick iron plate. In the vibration test, the conductor plates of different materials work in the air gaps of 10 mm, 20 mm, 30 mm, 40 mm. The test results show that the iron plate is added after the copper plate, and the damping is increased to 1.9 times and 1.4 times when the copper plate and iron plate are used alone. The air gap is a critical factor affecting the eddy current damping. When the air gap increases, the damping ratio will decrease rapidly. Adjusting the air gap dimension is the most effective and easiest method to change the damping ratio. The maximum damping ratio provided by the damper is 15.40%, which proves that it has a strong energy dissipation ability.