On the dynamic stochastic response of FE models

A numerical procedure to compute the mean and covariance matrix of the response of nonlinear structures modeled by large FE models is presented. Non-white, non-zero mean, non-stationary Gaussian distributed excitation is represented by the well known Karhunen–Loéve expansion, which allows to describe any type of non-white Gaussian excitation in contrast to filtered white noise which might not be easily adjusted to available statistical data. The solution procedure differs considerably from standard methodologies using a state space representation. In the proposed approach, step-by-step integration procedures developed for deterministic FE analysis are applied to compute the first two moments of the stochastic response.