Study on enhanced performance of CuFe alloy's eddy current damping and its advantages in multi-mode vibration control of stay-cable

Abstract

This study presents an innovative solution to address the performance degradation of eddy current dampers (ECD) at high speeds. It replaces the traditional copper conductor with a magnetically and electrically conductive CuFe alloy. The damping force equation for this CuFe alloy-based ECD (CuFe-ECD) is derived and validated through rotor experiments and a simplified finite element model. Results confirm that CuFe alloy enhances damping performance, with CuFe20 exhibiting outstanding quasi-bilinear characteristics, particularly at higher speeds. CuFe10, CuFe15, and CuFe30 also demonstrate similar behavior. The study explores the impact of CuFe alloy properties (conductivity, permeability, and thickness) on the bilinear damping curve. CuFe alloys notably reduce magnetic reluctance, especially in thicker conductors, mitigating skin effect and armature reaction in the electromagnetic field. Finally, the CuFe-ECD is utilized for multi-mode vibration control using the long cable of the Sutong Bridge. The results indicate that the modal damping ratios of modes 1st-20th can reach 5‰, which is superior to other schemes. In high-order modes, the damping ratio of the 35th-40th modes still stabilizes at 3.72–3.90‰. It can be concluded that the bilinear damper has significant advantages in multi-mode vibration control: compared with the single linear damper scheme, it can improve the vibration reduction effect of multi-mode control, and compared with the dual linear damper scheme, it can reduce the number of dampers and achieve better economic benefits.