VIBRATION RESPONSE OF CABLES IN CABLE-STAYED SPATIAL STRUCTURES UNDER AXIAL EXCITATION

The dynamic response of cables without damping in cable-stayed spatial structures (CSS) under axial excitation is investigated. The non-linear vibration equations of cables with the consideration of interaction among tower columns, cables, spatial structures are given. The multiple scale method (MSM) is introduced to analyze the characteristics of cable’s vibration, and the precise time-integration method (PTIM) is used to solve vibration equations. It is shown from the results that the characteristics of cable vibration is closely relative to the frequency ratio of tower columns, cables and spatial structures, as well as the initial disturbances caused by the vibration of the tower columns and the spatial structures. The parametric vibration response of cables is significantly influenced by the vibration of tower columns. The divergent vibration arises in the free vibration of cable without damping if the natural frequencies of tower columns and spatial structures are very close, but are far from the natural frequencies of cables. On the other hand, the “beat” feature of cable free vibration occurs, if the natural frequencies between tower columns and spatial structures are approximately the same and slightly different from those of cables. The displacement amplitude of cable vibration is very close to the magnitude of its initial disturbance if natural frequencies among cables, tower columns and spatial structures are almost the same.