Strong mode localization in nearly periodic disordered structures

International audienceAn investigation of the effects of disorder on the dynamics of nearly periodic structures is presented. Emphasis is placed on the study of mode localization and vibration-confinement phenomena for mistuned assemblies of coupled, multi-degree-of-freedom component systems. Perturbation methods are developed and applied to predict the occurrence of localized modes and analyze their characteristics. Strong localization is shown to occur for weak coupling between component systems. Furthermore, a "modal" coupling parameter is defined that governs the possibility for localization in a given mode. Generally speaking, higher modes are shown to be more susceptible to localization than lower ones, and localization is unavoidable if the mode number is large enough. The occurrence of localization is also shown to be dependent upon the location of the coupling constraint between the component systems