Robust Vibration Suppression of Resonant Modes by Feedback Compensation Realized Using Allpass Filters

In this study, we used two tunable vibration absorbers composed of shape memory alloy to reduce vibration of a platform structure. The natural frequency of the shape memory alloy absorber can be tuned online using a fuzzy logic controller to change the axial force of the shape memory alloy wires through phase transformation. In addition, we employed the finite element method to analyze the dynamic characteristics of the multimode platform structure and to evaluate the effectiveness of the shape memory alloy vibration absorber in terms of platform vibration attenuation. Experimental testing of the platform structure was conducted to verify its modal characteristics. By setting the two shape memory alloy tunable vibration absorbers on two adjacent sides of the platform at 90 degrees to each other and offset from the platform’s center axes, it is shown that all six modes can be covered for vibration absorption. The experiments show that the vibration due to all six mode modal excitations can be attenuated by more than 7.49 dB using the shape memory alloy tunable vibration absorber. Specifically, at the fourth, fifth, and sixth resonant modes, an average of 16.68 dB vibration suppression is observed. Overall, an average of 12.69 dB vibration suppression is achieved for resonant excitation of the entire platform structure when using the designed shape memory alloy tunable vibration absorber.

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Optimal piezoelectric resistive–inductive shunt damping of plates with residual mode correction

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x18798953 ◽

2018 ◽

Vol 29 (16) ◽

pp. 3346-3370 ◽

Cited By ~ 7

Author(s):

Johan F Toftekær ◽

Ayech Benjeddou ◽

Jan Høgsberg ◽

Steen Krenk

Keyword(s):

Coupling Coefficient ◽

Electromechanical Coupling ◽

Vibration Suppression ◽

Equations Of Motion ◽

Open Circuit ◽

Electromechanical Coupling Coefficient ◽

Inertia Effects ◽

Resonant Modes ◽

Calibration Methods ◽

Shunt Damping

This work concerns vibration suppression of plates and plate-like structures by resonant piezoelectric damping, introduced by resistive–inductive shunts. The performance of this type of shunt damping relies on the precise calibration of the shunt frequency, where an important aspect is the ability to account for the energy spill-over from the non-resonant modes, not taken into account by most available calibration methods. A newly proposed calibration procedure includes this residual mode contribution by a quasi-dynamic modal correction, taking both flexibility and inertia effects of the non-resonant modes into account. In this work, this procedure is implemented in a finite element model combining Kirchhoff plate bending kinematics for the host structure and a plane stress assumption for a pair of bonded piezoceramic patches. The established model is verified by comparison with shunt calibrations from benchmark examples in the literature. As demonstrated by frequency response plots and the obtained damping ratios, the resistive–inductive shunt tuning is influenced by the effect of the non-resonant modes and omission may yield a significant detuning of the shunt circuit. Finally, an alternative method for precise evaluation of the effective (or generalized) electromechanical coupling coefficient is derived from the modal electromechanical equations of motion. This results in a new shunt tuning method, based on the effective electromechanical coupling coefficient obtained by the short- and open-circuit frequencies of the coupled piezo-plate structure.

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Spatial Vibration Control of Thin Beams Using Multimode Modified Positive Position Feedback

Volume 3: Industrial Applications; Modeling for Oil and Gas, Control and Validation, Estimation, and Control of Automotive Systems; Multi-Agent and Networked Systems; Control System Design; Physical Human-Robot Interaction; Rehabilitation Robotics; Sensing and Actuation for Control; Biomedical Systems; Time Delay Systems and Stability; Unmanned Ground and Surface Robotics; Vehicle Motion Controls; Vibration Analysis and Isolation; Vibration and Control for Energy Harvesting; Wind Energy ◽

10.1115/dscc2014-5867 ◽

2014 ◽

Cited By ~ 1

Author(s):

Ehsan Omidi ◽

S. Nima Mahmoodi

Keyword(s):

Vibration Suppression ◽

Experimental Results ◽

Controlled System ◽

Norm Minimization ◽

Positive Position Feedback ◽

Resonant Modes ◽

Vibration Attenuation ◽

Position Feedback ◽

High Level ◽

Thin Beams

Spatial multimode resonant vibration suppression using Modified Positive Position Feedback (MPPF) approach is presented in this paper. Spatial implementation of the MPPF controller considers vibration attenuation in the whole structure, rather than on a limited number of local control points. This approach utilizes spatial norm minimization of H2 and H∞, which considers vibration amplitude of all points on the structure in a model-based design. The designed controller is then evaluated using a clamped-clamped (c-c) and a cantilever beam as the test platforms. According to the numerical simulations and experimental results, spatial MPPF controller using both norm minimization techniques provides a high level of vibration suppression all over the structure, and for all active resonant modes. The MPPF-H∞ controlled system has a smoother response in the frequency domain, which is more preferable when the closed-loop system experiences a frequency sweep disturbance. At exact resonant frequency however, experimental results confirm a better suppression performance using the spatial MPPF-H2 method on different points of both beam structures.

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Introductory PZT Actuators Optimal Working Configuration Experimental Study in a Turbofan Engine Fan Rotor Blade

Volume 11: Structures and Dynamics: Structural Mechanics, Vibration, and Damping; Supercritical CO2 ◽

10.1115/gt2020-15547 ◽

2020 ◽

Author(s):

Fabio Botta ◽

Andrea Rossi

Keyword(s):

Rotor Blade ◽

Vibration Suppression ◽

Resonant Mode ◽

Turbofan Engine ◽

Active Systems ◽

Rotating Blade ◽

Modal Damping ◽

Resonant Modes ◽

Turbomachinery Blades ◽

External Forces

Abstract Vibration suppression systems are often crucial to extend the life cycle of the structures in several engineering fields. The passive systems are the most commonly used but, in case of dynamic loads, the active systems show a greater efficiency. Since the external forces acting on a rotating blade may excite several vibrational modes simultaneously, an active multi-modal damping device could enhance the damping action. The piezoelectric (PZT) actuators seem to be the most promising but their placing on the structure plays a crucial role. In this paper, some PZT actuators have been mounted on the surface of an actual rotor blade from the second fan stage of a turbofan engine and their working configuration has been optimized on the basis of a previously developed model. Thereby, the actuators are able to efficiently damp the most detrimental resonant mode or a resonant modes coupling. The experimental results show that the proposed system well suits the application and may be considered as an alternative method to deal with vibration issues in turbomachinery blades.

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