| Abstrakt: |
Purpose: In this paper, the nonlinear vortex-induced vibration of electrostatically actuated microbeam is studied based on modified strain gradient theory. The effects of mid-plane stretching, electrostatic actuation, Casimir and intermolecular forces are considered. Methods: By applying the Hamilton's principle, the governing equations of motion are derived by considering the three non-local Euler–Bernoulli, Timoshenko, and hyperbolic beam theories (HBT). The nonlinear governing equations of motion are discretized using the Galerkin method, and then the solution of the equation is determined by the numerical method. The dynamic response of the system, Fast Fourier Transform (FFT) spectrum, pull-in voltage, and amplitude-fluid flow velocity curves for different values of the small size effect parameter, applied voltage, and fluid flow velocity are extracted. Results: The results reveal that non-local HBT theory and for appropriate values of the small size parameter provides more accurate results than classical beam theory and the other two theories. It is observed that the presence of electrostatic force, shifting the range of the lock-in zone, and causes a significant increase in the maximum amplitude of the microbeam. Also, the results show that by increasing the fluid flow velocity, the influence of inertia on pull-in values considerably increases. Conclusion: In predicting the dynamic behavior of microbeams, the non-local hyperbolic beam theory has a greater accuracy than other models. It is worth mentioning that the parametric study is performed under relatively small deformation condition. In future work, the influence of nonlinear behavior and large deformations will be further investigated. [ABSTRACT FROM AUTHOR] |
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