Influence of stochastic perturbations of composite laminate layups on the aeroelastic flutter of a cantilevered plate wing

Abstract

A numerical study of the effect of uncertainties in ply angles and thicknesses on the flutter speed of a cantilevered composite plate wing was conducted in this paper. Reduction of the number of uncertain parameters was possible thanks to the use of the polar method, which also enabled a systematic analysis of the influence of material symmetries. From the polar domain of orthotropic laminates, several stacking sequences were reconstructed in order to propagate parametric uncertainties. Typical fabrication uncertainties on ply thicknesses and angles were considered in order to quantify their influence on the probabilistic aeroelastic response. The reduction of the set of stochastic parameters by the polar method enabled the use of a polynomial-chaos approach which was combined with machine-learning techniques in order to deal with the correlation and with discontinuities in the response surface. Results reveal that possible manufacturing tolerances cause significant deviations in the critical flutter speed from the nominal value, especially when mode switches occur. As these deviations surpass classical dimensioning margins, uncertainty quantification approaches can provide added safety.