Effects of Concentrated Mass on the In-Plane Dynamic Behaviors of Two-Cable Networks with a Cross-Tie

Abstract

This study proposes a two-cable network model, which includes a cross-tie and two concentrated masses installed at the connection points of cross-tie and cable. The characteristic equation of such a cable network system is formulated via the complex modal analysis method. Then, dynamics of a twin-cable network is discussed in details, and the effect of concentrated mass on the system modal frequencies, damping and mode shapes is investigated. Furthermore, a general two-cable network system is analyzed. Results show that the concentrated mass always reduces the modal frequency, as it causes an increase in the modal mass of the system. When installing a concentrated mass in a twin-cable network, the difference of vibration modes between the cables can be increased in the in-phase modes, thereby achieving the damping effect of the damping type cross-tie on these modes. For a twin-cable network with a viscous damper, a small concentrated mass can significantly increase the modal damping of the in-phase modes as long as the damping coefficient of the damper is properly set. Meanwhile, when there is a two-cable network with unequal length cables, the presence of concentrated masses may reduce differences in vibration modes between cables, thus leading to decreased damping of some modes.