*Result*: Multiscale Analysis of Vibration Performance of Composite Sandwich Beam Structures With FG‐CNT Reinforced Faces.

*The laminated composite structure with viscoelastic material inserted provides excellent performance of vibration and noise suppression, which has been extensively deployed for industrial applications, such as rail transportation. In this work, the aim is to present the dynamics performance of FG‐CNT reinforced composite (FG‐CNTRC) sandwich beam structures by conducting detailed parametric studies of fundamental frequency (FF) and loss factor (LF), to give a reference for engineers to develop composite structures with great stiffness and damping. The extended mixture rule method and first‐order discrete layer model are applied to deduce the effective properties of FG‐CNTRC faces and the vibration differential equations of FG‐CNTRC sandwich structures, respectively. Five stacking configurations of FG‐CNTRC faces are considered. Subsequently, the Hamilton approach is applied to build the vibration differential equations, and these equations are solved using the Navier method. Finally, the change rule of structural stiffness and damping properties is explored, as follows: First, the FF gradually becomes large, and the LF gradually decreases with the volume fraction of CNTs enlarging. Second, dimensionless FF gradually increases, and the LF first increases and then decreases with the enlarging of the thickness ratio of two composite layers. Third, with the enlarge of h2/h ratio, FF always diminishes, but when a/h is bigger, LF first rises then diminishes, and when a/h is smaller, LF increases gradually. [ABSTRACT FROM AUTHOR]*