Analytical assessment of stay cable vibration mitigation using shape memory alloy wire

Abstract

The stay cables are axial load-carrying members in cable-stayed bridges and are subjected to the problems of large amplitude oscillations mainly due to wind. The investigations presented in this paper attempt to tackle the problem by the application of a shape memory alloy wire, which are understood to have excellent recovery property under large deformation. The aim is to determine how the dynamic behavior of a taut steel cable changes when a Ni-Ti SMA wire is connected to the cable and which location of SMA at the taut cable may provide the best results in terms of vibration dissipation of the cable. Before the analytical study on the taut cable, the behavior of Ni-Ti SMA wire in hysteresis was studied under different strain as well as in tension and compression loadings. The responses of the cable with and without SMA wire were determined in free as well as in forced vibrations. The SMA wire was used at different locations of the cable to determine its most effective location and the damping introduced to the cable. The variation of the amplitude response is investigated at varying excitation frequencies. It is found that the SMA wire can be effectively used as a damping element in dissipating the cable oscillation. It is also found that the mid-length of the cable where maximum amplitude dissipation occurs is the best location, although not a practical one, to attach the SMA wire.