Cylindrical functionally graded shell model based on the first order shear deformation nonlocal strain gradient elasticity theory

Abstract

In this article, a cylindrical functionally graded shell model is developed in the framework of nonlocal strain gradient theory for the first time. For this purpose, the modeled cylindrical FG nanoshell, its equations of motion and corresponding boundary conditions are derived by Hamilton’s principle and the first-order shear deformation theory. Generalized differential quadrature method is applied to discretize the equations of motion. The results of the proposed model are compared with those of the Eringen’s nonlocal, strain gradient, modified couple stress and classical theories. The conclusion of this comparison is that the nonlocal strain gradient theory combines advantages of nonlocal and strain gradient theories by applying both material length scale parameter and a nonlocal parameter in the model to consider the significance of strain gradient stress field and nonlocal elastic stress field, respectively. Furthermore, the effects of the material length scale, nonlocal parameter, FG power index, circumferential wave numbers and length of shell on vibrational behavior of the nonlocal strain gradient FG nanoshell for simply supported and clamped–clamped boundary conditions are investigated.