Moment equation method for the nonlinear stochastic dynamic analysis of a wind-excited suspended cable

This paper presents a moment equation approach for the probabilistic characterization of the response of wind-excited suspended cables. The procedure accounts for geometrical nonlinearities inherent in cable behaviour, wind-structure interaction and spatial correlation of wind turbulence field. The equations governing cable motion are reduced through the joint application of Galerkin’s method and the spectral decomposition of the cross-power spectral density function of wind turbulence field. In order to apply Itô stochastic differential calculus, the fluctuating component of each generalized aerodynamic load is modelled as the output of an appropriate linear digital filter excited by a Gaussian white noise. Then, the infinite hierarchy of differential equations ruling the statistical moments of cable response is written and an approximate solution is pursued by applying Gaussian Closure technique.