AN EXPERIMENTAL STUDY OF INTRINSIC LOCALIZED MODES FOR DAMAGE IDENTIFICATION IN PERIODIC STRUCTURES

摘要

Periodic arrays of discrete nonlinear oscillators may exhibit a phenomenon termed intrinsic localized modes (ILMs), in which areas of localized energy are triggered. This research hypothesizes that exploiting the unique localization of energy produced by ILMs in periodic structures may be strategically utilized to detect damage within the structures. To explore the idea, this paper presents an experimental study of the opportunities enabled by triggering and steering ILMs through a periodic structure composed of nonlinear, cantilevered beams which contain a stiffness defect representative of a damaged array site. The investigations show that the particular behaviors of ILMs moving within a damaged structure, as compared to within the healthy periodic system, may be used to identify the presence as well as the approximate location of the damage. Strategies to guide the ILM within the periodic structure are explored for their application to situations in which deliberate energy-steering is favorable. The findings show that ILMs is a robust phenomenon and their strategic employment presents novel opportunities to advance the aims of structural damage identification.