THE THEORY OF RESPONSE ANALYSIS OF FUZZY STOCHASTIC DYNAMICAL-SYSTEMSWITH A SINGLE DEGREE-OF-FREEDOM

Most real-life structural/mechanical systems have complex geometrical and material properties and operate under complex fuzzy environmental conditions. These systems are certainly subjected to fuzzy random exci tations induced by the environment. For an analytical treatment of suc h a system subjected to fuzzy random excitations, it becomes necessary to establish the general theory of dynamic response of a system to fu zzy random excitations. In this paper, the theory of response, fuzzy m ean response and fuzzy covariance response of a single-degree-of-freed om (sdf) system to fuzzy random excitations in the time domain and fre quency domain is put forward. The theory of response analysis of an sd f system to both stationary and non-stationary fuzzy random excitation s in the time domain and frequency domain is established. Two examples are considered in order to demonstrate the rationality and validity o f the theory, and the models of stationary filtered white noise and no n-stationary filtered white noise fuzzy stochastic processes of the ea rthquake ground motion are set up. Methods of analysis for fuzzy rando m seismic response of sdf systems are put forward using the principles of response analysis of an sdf fuzzy random dynamic system.