Novel lightweight materials are being used more and more in the aerospace industry, to reduce aircraft weight while maintaining or even improving strength and stiffness. Due to increased number of intrinsic variables of these materials and to higher variability in the physical and geometrical properties, accurate predictions of structural behavior can only be obtained with a new methodology based on reliability analysis and design optimization through probabilistic models.
This paper intends to give a mathematical overview of the most used algorithms for reliability analysis using limit state approximations, such as FORM and SORM. The advantages and disadvantages of the application of these methods and of the particular stochastic characterization used for the input variables are pointed out, with particular focus on computational issues that might arise through the application of reliability analysis to Finite Element models. Suitable methods are demonstrated on a FE model of a composite wing with a highly non-linear behavior.
