Probabilistic flutter analysis with uncertainties in structural stiffness

A probabilistic flutter analysis method was proposed to evaluate the structural stability and flutter risk of the rudder, which was subject to uncertainties in structural parameters with stochastic distribution. Monte Carlo simulation (MCS) and non-intrusive polynomials chaos (NIPC) method were used. A typical 3-D rudder with nonlinear factors, whose steering gear has two uncertain variables, that is bending rigidity and torsional rigidity, both satisfying Gauss distribution, was selected to examine the present method. A large amount of flutter information was obtained by flutter calculations of massive samples when using the MCS method, while which was gotten by surrogate models with point-collocation method when using the NIPC method. After that, the dangerous regions of velocity and the probability of flutter under certain velocity were obtained. Then the comparisons of the confidence level, analytic precision and efficiency of calculation were conducted. The results suggest that the probabilistic flutter analysis method based on uncertainty quantification is effective in the flutter risk assessment of structures using the probability information of the uncertain parameters.