Uncertainty analysis of natural vibration characteristics of composite laminated plates with spatially varied stochastic volume fractions

In each layer of the composite laminate, the spatial uncertainty effect of the volume fraction was considered. Using exponential autocorrelation function, the relationship between the volume fraction of each layer and the spatial position was simulated. Combining the Galerkin-Riza discretization and K-L series expansion methods, the influence of autocorrelation length on the discretization accuracy was carried out. The stochastic finite element model of composite laminates with spatially random material properties was established. Taking the T300 carbon fiber/QY8911 epoxy aircraft vertical tail thin-gauge skin structure as an example, the relationships between the mean value, standard deviation and coefficient of variation of the natural frequency and the number of laminate layers were obtained. And the Monte-Carlo simulation method was used to verify the effectiveness of the method in this paper to carry out the natural frequency and mode uncertainty analysis of composite laminates. The results show that: the coefficient of variation of the natural frequency of the composite laminate structure increases with the decrease of the number of layers, and the less the number of layers, the greater influence of uncertainty of the fiber volume fraction on dispersion of the natural vibration characteristics.