A corotational finite element to model galloping vibrations of overhead electrical lines

The present work deals with a numeric procedure developed for the study of the nonlinear motion of overhead electrical lines interacting with a wind flow. The large displacements and rotations related to the behavior of flexible systems require a particular Finite Element formulation to describe the exact position and orientation of each part of the structure during motion. Two different Finite Elements are superimposed, at each time instant, to model this kind of systems: an isoparametric “aerodynamic element” to evaluate the aerodynamic forces at the nodes in the current deformed configuration of the structure, and a corotational “mechanical element” to compute the mechanical response of the overhead conductor itself. Both elements take into account the flexural and torsional rotations of the conductor. The proposed formulation is applied to a well known numerical example for the study of the galloping vibrations under steady wind conditions and for a 3D turbulent wind field.