حديث غفاري

The research aims to investigate the nonlinear vibration and stability of electrically-actuated flexoelectric nano-switch. The considered switch is subjected to an electrostatic actuation with fringing field effect, Casimir force, piezoelectric voltage and temperature change. The electrostatic actuation consists of both DC and AC voltages. Mathematical formulation is established considering Euler-Bernoulli beam theory with consideration of von-Karman geometrical nonlinearity and nonlocal strain gradient theory (NSGT). Utilizing the Hamilton’s principle, the governing equation of the problem is obtained. At first, by neglecting the timedependent terms, the static displacement and pull-in voltage of the system are acquired. Then, after applying Galerkin’s approach as a discretization method, the multiple scales method is employed to solve the achieved equation analytically. Frequency-response curve relation is calculated and the influences of various involved parameters such as flexoelectricity, piezoelectric voltage, thickness stretching, and temperature change on the dynamic response of a clamped-clamped nano-switch is eva‎luated. As an important result, it is shown that by considering thickness stretching effect for a nano-switch with a high DC voltage, the system might exhibit stiffness-hardening phenomenon rather that stiffness-softening. Therefore, for predicting exact and accurate dynamic response, it will be necessary to account for the thickness stretching effect. Also, the other parameters such as piezoelectric voltage and temperature change exhibit a substantial effect on stiffness hardening, peak of frequencyresponse curve and multi-value solution which contains an unstable dynamical solution.

فلكسوالكتريك , روش مقياس هاي زماني چندگانه , ناپايداري پولين , منحني پاسخ فركانسي , سوييچ , ولتاژ پيزوالكتريك

Flexoelectric , Multiple scales method , Pull_in instability , Frequency response curve , Switch , Piezoelectric voltage

Hadis Ghafari

Dr. Kamran Daneshjoo_Dr. Roohollah Talebitooti