Force appropriation of nonlinear structures. (30th June 2018)

• Record Type: Journal Article
• Authors: Renson, L.; Hill, T. L.; Ehrhardt, D. A.; Barton, D. A. W.; Neild, S. A.
• Is Part Of: Proceedings. Volume 474:Number 2214(2018)
• Publication Date: 2018-06-30
• Subjects: nonlinear normal modes -- phase quadrature -- force appropriation -- energy transfer -- nonlinear dynamics; Physical sciences -- Periodicals; Engineering -- Periodicals; Mathematics -- Periodicals; 500
• DOI: 10.1098/rspa.2017.0880
• Languages: English
• ISSNs: 1364-5021

Abstract

Abstract : Nonlinear normal modes (NNMs) are widely used as a tool for developing mathematical models of nonlinear structures and understanding their dynamics. NNMs can be identified experimentally through a phase quadrature condition between the system response and the applied excitation. This paper demonstrates that this commonly used quadrature condition can give results that are significantly different from the true NNM, in particular, when the excitation applied to the system is limited to one input force, as is frequently used in practice. The system studied is a clamped–clamped cross-beam with two closely spaced modes. This paper shows that the regions where the quadrature condition is (in)accurate can be qualitatively captured by analysing transfer of energy between the modes of the system, leading to a discussion of the appropriate number of input forces and their locations across the structure.