Eddy-current inertial mass damper for cable vibration control
Wang Zhihao1 Cheng Zhipeng1 Wang Hao2 Yue Fangfang1 Gao Hui2
1. North China University of Water Resources and Electric Power, Zhengzhou 450045, China;
2. Key Laboratory of Concrete and Prestressed Concrete Structure of the Ministry of Education, Southeast University, Nanjing 210096, China
Abstract：To enhance vibration control performance of conventional passive viscous dampers (VDs) on stay cables, this study proposes a new cable vibration control using the eddy-current inertial mass damper (ECIMD), which combines rotary eddy-current damping with a two-node inertial element based on the ball screw. Firstly, an ECIMD prototype with adjustable damping coefficient and inertial mass was developed, and its mechanical parameters were identified via mechanical performance tests. Subsequently, the effects of the damping coefficient and the inertial mass of ECIMD on the first three supplemental modal damping ratios of the cable were experimentally investigated through model cable tests. Next, various analysis models of the cable-ECIMD system, considering the influence of cable sag, bending stiffness and boundary conditions, were established using the finite difference method, and the predicted supplemental modal damping ratios of the cable were compared with corresponding experimental results. Finally, parametric optimization for multi-mode cable vibration mitigation using the ECIMD was performed. The results show that the equivalent eddy-current damping coefficients of the ECIMD decrease gradually with the increase of the excitation frequency, which is particularly beneficial to mitigating cable multi-mode vibration. Considering the cable sag and bending stiffness, the analysis model of the fixed-end cable-ECIMD system can be used to conservatively estimate the attainable supplemental modal damping ratios of the cable. The ECIMD shows superior performance over the VD for both single-mode and multi-mode vibration mitigation of the stay cable.
