On the effect of viscoelasticity on behavior of gyroscopes

Abstract

In the present study, the size- and time-dependent viscoelastic bending analysis of rotating spherical nanostructures made of functionally graded materials (FGMs) is performed. To simulate gyroscopic rotation, the structure is assumed to be rotated around two axes with constant angular accelerations. The nonhomogeneous nanostructure with functionally variable thickness (FVT) is assumed as FGM/FVT structure. Geometrically, the inner side of the structure has a spherical shape and the outer side is considered as an ellipse or any other arbitrary function. The size-dependent governing equations and related boundary conditions are obtained by implementing Hamilton's principle based on Eringen's nonlocal elasticity and first-order shear deformation theories. The resulting equations are solved using the Semi-Analytical Polynomial Method (SAPM). The time-dependent deflection is obtained by applying the boundary and initial time conditions. The effects of a hygro-thermal environment and porosity are also considered for a comprehensive analysis. Since no research has been conducted so far on the nonlocal viscoelastic dynamic analysis of FGM/FVT gyroscopes, the classical results are compared with the previously published works and ABAQUS software as well as the effect of many parameters on the results including nonlocality, FGM properties of the structure, thickness changes, angular velocities and accelerations, hygro-thermal environment, porosity, and viscoelastic properties are thoroughly conducted.