VIBRATION BEHAVIOR OF HYBRID FRP CABLE UNDER INDIRECT EXCITATION

摘要

This paper presents the vibration behavior of hybrid FRP cable subjected to indirect excitation including external and parametric excitation, respectively. The background of applying hybrid basalt and carbon FRP (B/CFRP) cables in thousand-meter scale cable-stayed bridge and the studies on cable vibration were first introduced, based on which the advantages of hybrid B/CFRP cable, especially with self-damping design, were clarified. The detailed constitution and principle of self-damping design and the evaluation of the corresponding damping ratio were described then. The primary resonance responses of self-damping hybrid B/CFRP, as well as steel, CFRP and hybrid B/CFRP without self-damping cables, were analyzed in terms of dynamic equilibrium equations. The results show that (1) under external excitation, the amplitude of resonant vibration of self-damping hybrid B/CFRP cable exhibits approximate linearity and shows much smaller value compared with that of the other cables, meanwhile self-damping hybrid B/CFRP cable manifests much smaller increment of tension compared with steel cable; (2) the resonant vibration of self-damping B/CFRP cable can be only excited by relatively large amplitude of parametric excitation and the amplitude is smaller than that of the other cables, similarly, smaller increment of cable tension of self-damping hybrid B/CFRP cable are observed in comparison with that of the steel cable; (3) parametric excitation shows more significant influence to the resonant vibration of all of the cables, which is supposed to be investigated further.