Dynamic Stability of Imperfect Cable Stayed Masts

Abstract

Cable stayed masts are used in several engineering applications. In this work, the nonlinear finite element method, using an updated Lagrangian formulation, is used to study the effect of initial geometric imperfections on the non-linear vibrations of cable stayed masts subjected to axial time dependent loads. The non-linear equations are solved using the Newton-Raphson method associated to an arc-length technique and the Newmark method is used to calculate the time responses of the system. Validation examples are presented and the influence of initial geometric imperfections and cable tensioning is studied when stayed towers are subjected to different types of axial loads. The Budianski´s criterion is used to study the loss of stability under sudden and harmonic loads. Obtained numerical results show the great influence of both cable tensioning and cable positioning on the nonlinear behavior of the system and could be used as a tool for an analysis of the nonlinear dynamics of the structure previous to design.