Journal article 1033 views 186 downloads
Application of control-based continuation to a nonlinear structure with harmonically coupled modes
Mechanical Systems and Signal Processing, Volume: 120, Pages: 449 - 464
Swansea University Author:
Alexander Shaw
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DOI (Published version): 10.1016/j.ymssp.2018.10.008
Abstract
This paper presents a systematic method for exploring the nonlinear dynamics of multi-degree-of-freedom (MDOF) physical experiments. To illustrate the power of this method, known as control-based continuation (CBC), it is applied to a nonlinear beam structure that exhibits a strong 3:1 modal couplin...
Published in: | Mechanical Systems and Signal Processing |
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ISSN: | 0888-3270 |
Published: |
2019
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Online Access: |
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URI: | https://cronfa.swan.ac.uk/Record/cronfa44937 |
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Abstract: |
This paper presents a systematic method for exploring the nonlinear dynamics of multi-degree-of-freedom (MDOF) physical experiments. To illustrate the power of this method, known as control-based continuation (CBC), it is applied to a nonlinear beam structure that exhibits a strong 3:1 modal coupling between its first two bending modes. CBC is able to extract a range of dynamical features, including an isola, directly from the experiment without recourse to model fitting or other indirect data-processing methods.Previously, CBC has only been applied to (essentially) single-degree-of-freedom (SDOF) experiments. This is the first experimental demonstration of CBC in the presence of complex MDOF response features such as internal resonance, isola, and Neimark-Sacker bifurcations. In this paper we show that the feedback-control methods and path-following techniques used in a SDOF context can equally be applied to MDOF systems. A low-level broadband excitation is initially applied to the experiment to obtain the requisite information for controller design and, subsequently, the physical experiment is treated as a “black box” that is probed using CBC. The invasiveness of the controller used is analysed and experimental results are validated with open-loop measurements. Good agreement between open- and closed-loop results is achieved, though it is found that care needs to be taken in dealing with the presence of higher-harmonics in the force applied to the structure. |
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Keywords: |
Nonlinear dynamics, Experiment, Control-based continuation, Multi-degree-of-freedom, Modal interaction, Isola |
College: |
Faculty of Science and Engineering |
Start Page: |
449 |
End Page: |
464 |