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50 results on '"Fang, Shitong"'

1. A Nonlinear Damped Metamaterial: Wideband Attenuation with Nonlinear Bandgap and Modal Dissipation

Author

Zhao, Bao, Thomsen, Henrik R., Pu, Xingbo, Fang, Shitong, Lai, Zhihui, Van Damme, Bart, Bergamini, Andrea, Chatzi, Eleni, and Colombi, Andrea

Subjects
Physics - Applied Physics
Abstract

In this paper, we incorporate the effect of nonlinear damping with the concept of locally resonant metamaterials to enable vibration attenuation beyond the conventional bandgap range. The proposed design combines a linear host cantilever beam and periodically distributed inertia amplifiers as nonlinear local resonators. The geometric nonlinearity induced by the inertia amplifiers causes an amplitude-dependent nonlinear damping effect. Through the implementation of both modal superposition and numerical harmonic methods the finite nonlinear metamaterial is accurately modelled. The resulting nonlinear frequency response reveals the bandgap is both amplitude-dependent and broadened. Furthermore, the modal frequencies are also attenuated due to the nonlinear damping effect. The theoretical results are validated experimentally. By embedding the nonlinear damping effect into locally resonant metamaterials, wideband attenuation of the proposed metamaterial is achieved, which opens new possibilities for versatile metamaterials beyond the limit of their linear counterparts.

Published
2023
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36. Continuous finite-time sliding mode control for synchronization of perturbed bistable electrostatic and piezoelectric transducers with external disturbances.

Author

Fang, Shitong, Mirzaei, Mohammad Javad, Asadollahi, Mostafa, Chen, Keyu, and Liao, Wei-Hsin

Subjects
*SLIDING mode control, *PIEZOELECTRIC transducers, *TRANSDUCERS, *CHAOS synchronization, *SYNCHRONIZATION, *VISUAL perception
Abstract

Despite that the synchronization of chaotic systems has been extensively investigated and demonstrated to contribute to physical, chemical, financial, and biological applications, the synchronization of different perturbed bistable systems appears to be an open issue. This is significant with the fact that the bistability widely exists from the visual perception to the electrical and mechanical systems. Therefore, this paper proposes a continuous finite-time terminal sliding mode control method to synchronize two bistable electromechanical transducers, with the electrostatic one acting as the master system and the piezoelectric one acting as the slave system. The model of two systems as well as the control method considering external disturbances and unmodeled dynamics are presented. Numerical simulation results show that two bistable systems can be synchronized with our proposed control method in intrawell, chaotic, and interwell oscillation modes. Furthermore, the chattering issue in conventional discontinuous controllers is eliminated with our designed continuous finite-time terminal protocols for bistable chaotic systems so as to improve the robustness of the controller and avoid its failure. Interesting findings are discussed for the varying system responses and control inputs in different oscillation modes. This work also is expected to facilitate the development of applications where bistability is found such as power or communication systems to resist the external disturbances. [ABSTRACT FROM AUTHOR]

Published
2023
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42. A nonlinear piezoelectric energy harvester with auxetic structures

Author

Chen, Keyu, Gao, Qiang, Fang, Shitong, Zou, Donglin, Yang, Zhengbao, Liao, Wei-Hsin, Chen, Keyu, Gao, Qiang, Fang, Shitong, Zou, Donglin, Yang, Zhengbao, and Liao, Wei-Hsin

Abstract

In this paper, we design and experimentally validate an auxetic nonlinear piezoelectric energy harvester. This harvester combines a clamp-clamp beam and auxetic structures, which can improve the efficiency and bandwidth of the energy harvesting based on a pure mechanical structure without outer magnets or stoppers. Finite element analysis is performed to analyse the effects of the auxetic structures on the efficiency and nonlinearity of the energy harvester. The lumped parameter model is utilized to predict the performance of the energy harvester, which well matches the experimental results. In the experimental validation, under 0.1g base excitation, the power output of the two types of auxetic energy harvesters is 173% and 94% higher than the conventional nonlinear energy harvester. Besides, the bandwidths of the two types of auxetic energy harvesters are broadened by 1556% and 2142% compared with the linear systems. © 2021 by ASME.

Published
2021

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