Sensitivity analysis for statistical characterization of uncertain systems

Vibrations of continuos structures depend on boundary conditions and physical parameters: uncertainties in any of them affect their dynamic behaviour, and, especially at high frequencies, the dynamic response of structures is more significantly described by a statistical model. In this paper a sensitivity analysis to variations of boundary conditions and physical parameters is presented that provides a simple criterion for establishing the need of a statistical approach. Numerical examples performed on one and two-dimensional systems are presented to confirm some analytical developments.