Nonlinear Vibration of Prestressed Fish-shaped Cable Truss Supporting System

摘要

The traditional dynamical calculation method for rigid structure can't be directly used for the prestressed fish-shaped cable truss, as it is a wind-sensitive structure. As the basis of response analysis of prestressed fish-shaped cable truss under seismic load, the nonlinear vibration of fish-shaped cable truss supporting system is investigated. First, the shape function and vibration displacement function for the prestressed fish-shaped cable truss are established through contact conditions. Subsequently with the continuous theory the dynamics equations of prestessed fish-shaped cable truss are got. Then Galerkin's method is used to discrete the dynamics equations into ordinary differential equations and L-P method is used to get the free vibration approximate solution. The modal analysis is carried out by using the finite element program ANSYS, the calculation of ANSYS and the results are similar, which verifies the reliability of this method. Lastly, the effects of temperature, amplitude, and initial tension on the nonlinear vibration are discussed with the engineering example. The example shows that the nonlinear vibration frequency of prestressed fish-shaped cable truss supporting system is higher than linear vibration frequency, and that natural frequency decreases with the increase of temperature, and increases with the increase of amplitude and initial tension.