首页|An iteration-free approach to excitation harmonization
An iteration-free approach to excitation harmonization
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NETL
NSTL
Elsevier
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.
Harmonic distortionShaker-structure interactionStepped sine testingModal interactionFrequency response
Patrick Hippold、Gleb Kleyman、Lukas Woiwode、Tong Wei、Florian Mueller、Christoph Schwingshackl、Maren Scheel、Sebastian Tatzko、Malte Krack
NETL
NSTL
Elsevier
