A technique of closure using a polynomial function of Gaussian process

The purpose of the paper is to present a closure technique based on the representation of the non-linear system response process to a random excitation by a polynomial function of Gaussian process. It is shown that for the unimodal and bimodal situations of the Duffing oscillator, the proposed technique can give good approximate response moments as well as the probability density function and power spectral density of the system response.