Vibration of rotating microbeams with axial motion in complex environments

In the present paper, the size-dependent vibrations and stability of rotating microbeams with axial motion embedded in a viscous medium with different supported boundary conditions in humid-thermal-magnetic environments under gravitational and axial loads are studied based on the coupled stress theory and Rayleigh beam model. The dynamic equations of the system are derived using the Hamilton principle. Using the Galerkin method and solving the eigenvalue problem, the backward and forward vibrational frequencies and the instability thresholds of the system are obtained. Comparative studies are performed to validate the results of the present study. The effects of various key parameters such as rotary inertia factor, substrate damping, flexural stiffness ratio on system dynamics are examined. The results showed that magnetic fields improve system performance in contrast to humid environments. Also, when the axial motion of the system is in the opposite direction of gravitational acceleration, gravitational forces reduce the instability threshold of the system and can change the system stability evolution. It is also shown that increasing the rotary inertia factor reduces vibrational frequencies and system stability. The modeling and the results of the present study can be useful in the optimal design of microswitches.