Nonstationary Response of Large FE - Models

An algorithm for the computation of the stochastic non-stationary non-linear response of large FE-models is presented. In stochastic analysis, the response is described by the mean and covariance function and possibly by the probability distribution of the non-linear response. To estimate the covariance matrix, the method of Equivalent Statistical Linearization (EQL) is applied for linearizing all non-linear elements. The large fully populated and symmetric covariance matrix of dimension ¾Ò is described by the so called Karhunen-Loéve expansion representation, which allows a feasible description. In this context, an efficient procedure is suggested to determine the minimal number of Karhunen-Loéve vectors necessary to assure a sufficiently accurate representation. This method in fact allows to employ any available deterministic integration scheme to compute the Karhunen-Loéve vectors.