An assembled arc-shaped pendulum TMD with constant eddy current damping for structural vibration control

Pendulum tuned mass damper with eddy current damping (EC-PTMD) is a promising TMD device for vibration control of structures. Previous study focused primarily on the plate-like configuration of EC-PTMD, which motion of inertial mass is approximately horizontal. However, uneven distribution of damping force, non-constant damping and low energy efficiency will be resulted. This study developed a newly assembled pendulum tuned mass damper with constant eddy current damping (AEC-PTMD) in the form of arc. The proposed AEC-PTMD consists of a rigid suspension with sufficient lateral stiffness to keep inertial mass motion in a plane, the conductor plate fixed on the baseplate, and arc-shaped back iron acted as inertial mass placed on two sides of conductor plate. Meanwhile, the arc-shaped permanent magnets (PMs) are embedded into both sides of back iron to overcome the normal attraction and enhance greater magnetic density. Based on the Biot-Savart Law, the analytical expressions of magnetic flux distribution for arc-shaped PM are derived and assessed. Meanwhile, the effect of ferromagnetic media on magnetic flux distribution of arc-shaped PM is analyzed, which utilized a parameterization formula for the distance from the surface of the PM to a point outside. Further, the 3D finite element model (FEM) of an AEC-PTMD unit is established to evaluate the accuracy of the analytical results. A prototype of the proposed AEC-PTMD unit has been fabricated and laboratory experiments are conducted for the purpose of validating analytical and FEM results. All of these results have a good agreement.