ABSTRACT
This paper proposes efficient techniques to obtain effective quantities when confronted to complex structures in medium frequency vibrations including stochastic parameters such as interface parameters. The first ingredient is the use of a dedicated approach to compute the medium-frequency problem: the Variational Theory of Complex Rays (VTCR). Using two-scale shape functions that satisfy the dynamic equation and the constitutive relation, the VTCR can be seen as a power balance on the different interfaces between sub-structures. The second ingredient is the use of the Polynomial Chaos Expansion (PCE) to compute the random response. Since the only uncertain parameters (in this application: the complex connection stiffness) are those that appear in the interface equations, this approach lead to very small computation cost.