Improved dynamic analysis of structures with mechanical uncertainties under deterministic input

This paper addresses the dynamic analysis of linear systems with uncertain parameters subjected to deterministic excitation. The conventional methods dealing with stochastic structures are based on series expansion of stochas tic quantities with respect to uncertain parameters, by means of either Tay lor expansion, perturbation technique or Neumann expansion and evaluate the first- and second-order moments of the response by solving deterministic e quations. Unfortunately, these methods lead to significant error when the c oefficients of variation of uncertainties are relatively large. Herein, an improved first-order perturbation approach is proposed, which considers the stochastic quantities as the sum of their mean and deviation. Comparisons with conventional second-order perturbation approach and Monte Carlo simula tions illustrate the efficiency of the proposed method. Applications are di scussed in order to investigate the influence of mass, damping and stiffnes s uncertainty on the dynamic response of the system. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.