An iteration-free approach to excitation harmonization
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Sinusoidal excitation is particularly popular for testing structures in the nonlinear regime. Due to the nonlinear behavior and the inevitable feedback of the structure on the exciter, higher harmonics in the applied excitation are generated. This is undesired, because the acquired response may deviate substantially from that of the structure under purely sinusoidal excitation, in particular if one of the higher harmonics engages into resonance. We present a new approach to suppress those higher excitation harmonics and thus the unwanted exciter-structure interaction: Higher harmonics are added to the voltage input to the shaker whose Fourier coefficients are adjusted via feedback control until the excitation is purely sinusoidal. The stability of this method is analyzed for a simplified model; the resulting closed-form expressions are useful, among others, to select an appropriate exciter configuration, including the drive point. A practical, model-free procedure for the control design is suggested. The proposed method is validated in virtual and physical experiments of internally resonant structures, in the two common configurations of force excitation via a stinger and base excitation. Excellent performance is achieved when simply using the same control gains for all harmonics, throughout the tested range of amplitudes and frequencies, even in the strongly nonlinear regime. Compared to the iterative state of the art, it is found that the proposed method is simpler to implement, enables faster testing and it is easy to achieve a lower harmonic distortion.
Date Issued
2025-06-15
Date Acceptance
2025-04-08
Citation
Mechanical Systems and Signal Processing, 2025, 233
ISSN
0888-3270
Publisher
Elsevier
Journal / Book Title
Mechanical Systems and Signal Processing
Volume
233
Copyright Statement
© 2025 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1016/j.ymssp.2025.112732
Publication Status
Published
Article Number
112732
Date Publish Online
2025-04-26