SPECTRAL APPROXIMATION FOR WIND-INDUCED STRUCTURAL VIBRATION STUDIES

In this paper an efficient procedure for determining spectral moments of arbitrary order of the response of multi-degree-of-freedom (MDOF) l inear systems under linearized pressure actions due to wind turbulence is presented. The procedure is initiated by decomposing the n-variate incoherent wind field velocity into a sum of it independent totally c oherent wind field velocities. Then, the use of a standard discretizat ion procedure for approximating the frequency dependent eigenvalues an d eigenvectors of the power spectral density (PSD) matrix leads to a p olynomial representation of each component of the PSD matrix. Based on this representation, the spectral moments can be evaluated in a close d form without resorting to numerical quadrature. An illustrative exam ple is included.