Damping of a stay cable with two eddy-current inertial mass dampers: Theoretical analysis, experimental study, and parameter optimization

Recent studies have demonstrated that inerter-based dampers exhibit superior performance in mitigating cable vibration over conventional passive viscous dampers (VDs). This paper develops a new inerter-based damper called the eddy-current inertial mass damper (ECIMD), which consists of a rotary eddy-current damping element and a paralleled ball screw inertial mass element. Inspired by the advantages of two VDs on a single stay cable, the damping of a stay cable with two ECIMDs, either at opposite cable ends or the same cable end, was investigated through theoretical analysis, experimental study, and parameter optimization. First, the mechanical model of the ECIMD was derived from the geometrical configuration, and its effectiveness was verified through mechanical performance tests on two ECIMD prototypes. Subsequently, theoretical analysis models of the cable-ECIMD system were established by considering the cable sag, flexural stiffness, and boundary conditions. Furthermore, control performances of a model cable attached with two ECIMDs were experimentally evaluated. Finally, the multimode damping effect of two ECIMDs at the same cable end was highlighted through parameter optimization. Results show that when two ECIMDs are installed at opposite cable ends, the coupled single-mode damping effect of two ECIMDs is approximately the sum of individual contributions from each ECIMD. When mechanical properties of two ECIMDs at the same cable end can match well with each other, the coupled single-mode and multimode damping effect of two ECIMDs can be significantly enhanced compared with that of a single ECIMD installed at a further distance away from the cable anchorage.