Viscoelastic mechanics of Timoshenko functionally graded imperfect microbeams

A Timoshenko functionally graded (TFG) imperfect microscale beam is considered and the coupled viscoelastic mechanics is analysed in a nonlinear regime. Based on the Timoshenko beam theory, incorporating geometric imperfections, the Kelvin-Voigt method is used for internal viscosity, the rotary inertia is automatically generated due to the Timoshenko theory, and the Mari-Tanaka scheme is used for the mixture. After utilising the constitutive stress/strain relations, Hamilton's principle is used giving three sets of coupled motion equations. A discretisation is performed using Galerkin's method and numerical simulations, for mechanical behaviour analysis, are built upon a continuation method.