Design methods for the aerospace technology are

in general

based on deterministic parameters.In paractice there always exist random deviations of parameters

such as material properties and geometry

forces

and boundary conditions.In most situations the random deviations are small

but their overall effect can have a strong impact on behaviours of critical components

particularly in failure and reliablility analysis.For this reason a probabilistic finite element method based on second order perturbation technique is used to analyze the reliabilty and the random stresses of a rotating disk with uncertain geometery

the elementary perturbation approach to this problem has been studied and formulas for the random stress and the reliability have been deduced.The effect of uncertain geometery on the reliability is considered by a simple numerical example.The accuracy and efficiency of the method is demonstrated by its application to a rotating disk with uncertain geometery.The reliability calculated by this method compares favorably with that obtained from Monte Carlo simulation.