3aSA10. Response of mistuned, nonlinear cyclic assemblies to spatially distributed excitations.

Session: Wednesday Morning, December 4

Time: 10:35

Author: Melvin E. King
Location: Dept. of Aerosp. and Mech. Eng., Boston Univ., 110 Cummington St., Boston, MA 02215


In this work, the dynamics of weakly coupled, nonlinear cyclic assemblies are investigated in the presence of structural irregularities and spatially distributed excitations. A characteristic often found in weakly coupled, repetitive systems is mode localization, arising due to eigenvalue veering in mistuned linear systems and mode bifurcations in tuned nonlinear systems. The occurrence of localized modes in a repetitive system can lead to motions during which vibrational energy is spatially confined to a single substructure (strong localization) and/or several substructures (weak localization). Recent work by the author has investigated the combined effects of nonlinearities and structural mistunings in generating such localized motions. Using the method of multiple scale, the present work considers the response of mistuned assemblies to spatially distributed loading (both harmonic and transient). Under fundamental and/or subharmonic excitation, spatially extended, weakly localized and strongly localized responses are shown to exist for various structural parameters. The physical significance and stability characteristics of these motions will be discussed. Additionally, motion confinement characteristics will be demonstrated under transient loading conditions, and sample calculations will be presented for two, three, and four degree-of-freedom systems subjected to harmonic, base excitation. [Work supported by NSF.]

ASA 132nd meeting - Hawaii, December 1996