Mode localization and frequency loci veering in disordered engineering structures

Vibration mode localization and frequency loci veering in disordered struct ures of aircraft engineering are discussed in this paper. Three T-type beam models of disordered horizontal tails with rear fuselage, a model of two d isordered coupled control surfaces and a model of an aircraft with disorder ed external stores are adopted for the theoretical analysis. The matrix per turbation technique and the geometric theory are used to study the occurrin g mechanism of the two phenomena. Several simple criteria for predicting th e occurrence of the mode localization and frequency loci veering are given. The theoretical prediction of the phenomena is in great agreement with tha t obtained through numerical calculations of characteristic solutions of th e disordered structures. (C) 2000 Elsevier Science Ltd. All rights reserved .