Performance of a Novel Magnetic Stiffness-Adjustable Wire Rope Damper in High-Mode Vibration Control of Cables

This paper proposes a novel magnetic stiffness-adjustable wire rope damper (MSAWRD), which is implemented by connecting a wire rope damper (WRD) and a magnetic stiffness-adjustable device (MSAD). The application of WRDs in engineering practice has demonstrated their great potential in high-mode vibration control of cables. Nevertheless, the excessive stiffness of WRDs poses a constraint on the damping performance and increases the challenge in support design. The presence of the MSAD in the proposed damper aims to decrease adverse effects induced by the inherent stiffness of a WRD, thereby enhancing the effectiveness of a WRD-based damper in controlling high-mode vibrations of cable structures and reducing the demand for support stiffness. The proposed MSAD features a compact structure compared with conventional ones to broaden its application in confined spaces. Moreover, its negative stiffness can be readily adjusted, and the equilibrium position can be precisely determined using bolts. Cyclic loading tests on the WRD, the MSAD, and the MSAWRD are conducted in this study to elucidate their interconnection and damping behaviors. An analytical method is proposed for the MSAD and verified by experiments and numerical solutions. The hysteresis model of the MSAWRD is derived by combining the negative stiffness obtained from the analytical method with the modified Bouc–Wen model. Based on the developed hysteresis model, hybrid simulations are performed to evaluate the vibration behaviors of a long hanger installed with different dampers. It is found that the MSAWRD not only retains the advantages of the WRD (e.g., broadband applicability in high-mode vibration control) but also improves the vibration control performance by 22.7% and reduces the demand for damper support stiffness by 67.9%. These advantages will promote the application of the MSAWRD in cable vibration control.