Stochastic analysis of large structural systems under fully non-stationary input

Dynamic analysis of large linear systems is usually performed adopting the well-known modal analysis along with modal truncation of higher modes. However, in the case in which the contribution of higher modes is not negligible, modal correction methods have to be introduced to improve the accuracy of the dynamic response either in the case of deterministic or stochastic excitation. Aim of this paper is to propose a new computationally competitive method for the stochastic analysis of large linear system vibrating under fully non-stationary Gaussian excitations. The method is based on the extension of the mode-acceleration method and its variant, the stochastic mode-acceleration method, for the evaluation of the nongeometric spectral moments of the non-stationary response. Numerical results from the study of a large MDoF structure show the accuracy and the efficiency of the proposed technique.