An analytical approach for detecting isolated periodic solution branches in weakly nonlinear structures

Hill, T.L., Neild, S.A. and Cammarano, A. (2016) An analytical approach for detecting isolated periodic solution branches in weakly nonlinear structures. Journal of Sound and Vibration, 379, pp. 150-165. (doi: 10.1016/j.jsv.2016.05.030)

Abstract

This paper considers isolated responses in nonlinear systems; both in terms of isolas in the forced responses, and isolated backbone curves (i.e. the unforced, undamped responses). As isolated responses are disconnected from other response branches, reliably predicting their existence poses a significant challenge. Firstly, it is shown that breaking the symmetry of a two-mass nonlinear oscillator can lead to the breaking of a bifurcation on the backbone curves, generating an isolated backbone. It is then shown how an energy-based, analytical method may be used to compute the points at which the forced responses cross the backbone curves at resonance, and how this may be used as a tool for finding isolas in the forced responses. This is firstly demonstrated for a symmetric system, where an isola envelops the secondary backbone curves, which emerge from a bifurcation. Next, an asymmetric configuration of the system is considered and it is shown how isolas may envelop a primary backbone curve, i.e. one that is connected directly to the zero-amplitude solution, as well as the isolated backbone curve. This is achieved by using the energy-based method to determine the relationship between the external forcing amplitude and the positions of the crossing points of the forced response. Along with predicting the existence of the isolas, this technique also reveals the nature of the responses, thus simplifying the process of finding isolas using numerical continuation.

• Item Type: Articles
• Additional Information: The authors would like to acknowledge the support of the Engineering and Physical Sciences Research Council. T.L.H. and S.A.N. are supported by EP/K005375/1.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cammarano, Dr Andrea
• Authors: Hill, T.L., Neild, S.A., and Cammarano, A.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Journal of Sound and Vibration
• Publisher: Elsevier
• ISSN: 0022-460X
• Published Online: 10 June 2016
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in Journal of Sound and Vibration 379: 150-165
• Publisher Policy: Reproduced under a Creative Commons License