The present paper deals specifically with the frequently asked question of are there any differences between classical non-actuated mode-shapes of plate-type MEMS and the electrically deformed ones obtained by the non-classical modified couple stress theory. To this end, a Kirchhoff’s thin plate model together with the modified couple stress theory is considered to extract the eigenvalue problem which governs on free vibrations of the system. Using the free vibration equation of the system, it is proved that neither the electrostatic actuation nor the couple stress components influence on linear mode-shapes of the system. To emphasis on the validity of the present proof, the extended Kantorovich method is employed to provide analytical solutions for an electrically actuated micro-plate with clamped boundary conditions. The solutions, whose accuracy is verified by available results in the literature, also indicate that the linear mode-shapes of an electrically actuated micro-plate are totally independent from the influences of size and electrical loading.

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