A fuzzy stochastic correlation model for geometric imperfections of cylindrical shells

Abstract

Geometric imperfections are the major part of the disagreement between theoretically and experimentally determined buckling loads of thin walled cylindrical shells. In a common probabilistic approach the spatial varying imperfections are modeled as Gaussian random fields. Due to the underlying uncertainties like a small sample size or imprecise measurements it is practically impossible to define crisp input parameter for a random field representation, e.g., correlations. In this paper, the classical probabilistic approach is therefore extended to a fuzzy stochastic approach by using a polymorphic uncertainty model (fp-r) from Graf et al. (2015). This allows to take into account natural variability and incompleteness aiming to consider aleatory and epistemic uncertainties in a decision making process.