A STATIONARY MODEL FOR PERIODIC EXCITATION WITH UNCORRELATED RANDOM DISTURBANCES

The paper presents a stationary model for periodic excitations with ra ndom amplitude and phase disturbances for linear and nonlinear random vibration analysis. The disturbances are modeled as uncorrelated stati onary white noise processes. Application of the model is demonstrated by stationary moment response of a linear single-degree-of-freedom sys tem subject to such excitations. To find moment responses, an equivale nt augmented system subject to parametric white noise excitations unde r certain constraint conditions is studied. Numerical results for the second and fourth-order moment responses are presented. The probabilit y density function of the response is calculated based on the cumulant -neglect closure method. NonGaussianity of the response is discussed i n terms of the excess factor. The results show that the random amplitu de disturbance can significantly increase system moment response. The random phase modulation may increase or reduce the system moment respo nse, depending on the value of relative detuning between the system na tural frequency and the mean excitation frequency. The response may be come Gaussian in the sense of up to the fourth-order moment for suffic iently large random phase or relative detuning. Copyright (C) 1996 Els evier Science Ltd.