Nonlinear Vibration and Multimodal Interaction Analysis of Transmission Line with Thin Ice Accretions

Abstract

A study of multimodal galloping is carried out on an iced transmission line with thin ice accretions. The partial differential governing equations of iced transmission line are established to describe the nonlinear interactions between the in-plane, out-of-plane and torsional vibration, in which geometrical and aerodynamic nonlinearities are considered. The transformation of modal galloping with the continuous variations of parameters and modal interactions are analyzed based on the reduced model obtained by employing Galerkin spatial discretization. Eigenvalue analysis is applied on linear system to determine the switch of different modal galloping in plane U -l, where Hopf bifurcation occurs and mono-modal, bi-modal and multi-modal galloping are observed. Various numerical procedures are implemented to capture the outstanding nonlinear dynamic features of every regional galloping in plane U -l. Internal resonance is observed and investigated to interpret the phenomenon of modal transition which is also analyzed by accounting for the influence of initial conditions on galloping with either symmetric or anti-symmetric modes.