IDENTIFICATION FOR DYNAMIC STIFFNESS AND MODAL PARAMETER OF CABLES

The cable dynamic stiffness describes the load-deformation behavior of cables subjected to dynamic loading. It represents the intrinsic dynamic properties of cables. For the purpose of identification for cable modal parameter, the simplified cable dynamic stiffness is proposed based a closed-form expression of dynamic stiffness taking cable sag into account. A series of cable modal tests were conducted in the laboratory with different cable tension levels and corresponding frequency response functions were obtained. Based on the proposed simplified cable dynamic stiffness and measured frequency response functions, the cable frequencies and damping ratios have been successfully identified by using a least square curve fitting technique. Subsequently, a new method to estimate the modal parameters of cables is established.