A damped sandwich beam model based on symmetric-deviatoric couple stress theory

A size-dependent damped sandwich beam model is developed within the framework of symmetric-deviatoric couple stress theory (the modified version of couple stress theory proposed by Yang et al.) which contains only one material length scale parameter to interpret size effect in microstructures. The damped sandwich microbeam is composed of a viscoelastic core embedded between two elastic faces. Hamilton's principle in conjunction with symmetric-deviatoric couple stress theory is applied to obtain the size-dependent governing equations, boundary and initial conditions of the microbeam. Based on the new model, the influence of size-dependency due to the core and face layers on vibration damping characteristics of the microbeam is investigated.