Nonlinear dynamic analysis of guyed mast under random aerodynamic loading

Resumo

In this research, a guyed mast with non-linear behavior under random aerodynamic loading is modeled. It is a slender lattice metal structure, articulated at the base, stabilized by cables. An equivalent mass of the system concentrated at its upper end is admitted, whose displacements are the generalized coordinates of the system.  The model admits large displacements, leading to the need to consider geometric nonlinearity, that is, dynamic equilibrium is always imposed on the displaced position. The non-linear equations of motion are derived via direct
dynamic equilibrium. The numerical algorithm for simulating the response is based on step-by-step time integration using Runge-Kutta’s Method. The random aerodynamic loading is simulated by a Monte Carlo-type
procedure with superposition of harmonic series whose amplitudes are obtained from Power Spectrum Density Functions with randomly chosen phases. For application to the model under study, an equivalent point load is applied to the mass at the top of the mast. This procedure is inspired by the well-known Synthetic Wind Method.