Uncertainty Quantification in Flutter Analysis for an Airfoil with Preloaded Freeplay

摘要

InN CLASSIC aeroelasticity, the instability of flutter has beennstudied by a very deterministic method with the intent to avoidncatastrophic aircraft destruction. In this analytical method thenattributes and tests for items such as mass, stiffness, inertias, andndimension of the aircraft configurations are assumed to be the bestnestimation and deterministic values. In fact, however, these values arenvariable from one aircraft to another, due to the differences ofnmanufacturing run and operational condition. Recently, measure-nments of component weight and hinge line variation were conductednon a small sample size of 24 samples [1]. It shows that the weightnvariation is about 5% and hinge line inertia is about 20%. Thesenvariations are in fact parametric uncertainties. As a consequence, innorder to obtain the more reliable aeroelastic stability of system, wenshould take the effect of parametric uncertainties into the consid-neration. Parametric uncertainties owe their origin to many sources,nwhich include [2] 1) stochastic variations in material properties,n2) stochastic variations in structural dimensions, 3) stochasticnvariations in boundary conditions due to preload and relaxationnvariations in mechanical joints, and 4) stochastic variations ofnexternal excitations.