Forced vibration studies of sagged cables with oil damper using a hybrid method

This paper presents forced vibration studies of sagged cables with discrete oil dampers under harmonic excitation using an analytical/numerical hybrid method. The suggested hybrid method can take account of cable sag, cable internal damping, damper stiffness, damper mass, and others. The results show that an oil damper with appropriate parameters selected can effectively suppress the vibration of a cable under harmonic excitation. The cable sag, damper stiffness, cable internal damping, and others do affect damper performance. In particular, if a cable has symmetric modes of vibration near the frequency crossover points excited by harmonic loading, the damper may lose its function to suppress these modes of vibration. The possible reasons behind this and the measures to overcome the frequency crossover problem are explored and some preliminary results are presented.