EIGENFREQUENCIES CHARACTERISTIC ANALYSIS OF RANDOM STRUCTURAL SYSTEMS

In order to analyze the statistical characteristic of eigenfrequencies of stochastic structural systems, a stochastic finite element maximum entropy method was proposed on the basis of the dimension-reduction method. In this method, the multi-dimensional random eigenvalue functions were decomposed into the combination of one-dimensional random eigenvalue functions by the univariate dimension-reduction method, so the multi-dimensional integrations, which were employed to calculate statistical moments of eigenvalues of stochastic structural systems, were transformed into one-dimensional integrations, and the one-dimensional integration was calculated by the Gauss-Hermite numerical integration. After getting the first four origin moments of eigenfrequencies of stochastic structural systems, the explicit expressions of the probability density function of eigenvalues of structures were obtained using the Maximum Entropy Principle(MEP). The comparison of results between proposed method and Monte-Carlo simulation method demonstrates that the proposed method has small error, satisfactory computational accuracy and efficiency.