Localization phenomena in structural dynamics

A survey of vibration localization phenomena in the context of structural dynamics and vibrations is presented. The review covers the more common and relevant cases where mode localization and vibration confinement are likely to occur in engineering structures. Examples considered include periodic or nearly periodic multi-span beams and multi-bay trusses, large space structures, space antennas, and almost periodic (a.p.) structures with circular symmetry, e.g., bladed disks in turbomachines. Both analytical and numerical methods for analyzing and predicting localization in finite and infinite systems are discussed. In this paper, we show how the problem of mode localization and vibration confinement can be formulated as a problem in the theory of stability of differential equations with a.p. coefficients. Using stability theory, new definitions of mode localization can be established for both linear and nonlinear structures. The possibility of stabilizing certain nonconservative fluid-structure systems using structural disorder is demonstrated, and stability theorems are given for aeroelastic systems governed by normal operators. We also illustrate how the results from localization theory and the associated stability theory can be applied to the vibration control problem, by triggering vibration confinement by active or passive means. (C) 2000 Elsevier Science I-td. All rights reserved.