Orthotropic patterns of visco-Pasternak foundation in nonlocal vibration of orthotropic graphene sheet under thermo-magnetic fields based on new first-order shear deformation theory

In the present research, vibration and instability of orthotropic graphene sheet subjected to thermo-magnetic fields are investigated. Orthotropic visco-Pasternak foundation is considered to analyze the influences of orthotropy angle, damping coefficient, normal and shear modulus. New first-order shear deformation theory is utilized due to accuracy of its polynomial functions compared to other theories of plate. Motion equations are obtained by means of Hamilton's principle and then solved analytically. Influences of various parameters such as small scale, magnetic field, orthotropic viscoelastic surrounding medium, thickness and aspect ratio of single layer graphene sheet on the vibration characteristics of nanoplate are discussed in detail. The results indicate that the stability of single layer graphene sheet is strongly dependent on applied magnetic field. Therefore, the mechanical behavior of single layer graphene sheet can be improved by applying magnetic field. The results of this investigation can be used in design and manufacturing of micro/nano mechanical systems.