This paper presents a nonlocal strain gradient theory for capturing size
effects in buckling analysis of Euler-Bernoulli nanobeams made of threedimensional
functionally graded materials. The material properties vary
according to any function. These models can degenerate to the classical
models if the material length-scale parameters is assumed to be zero. The
Hamilton's principle applied to drive the governing equation and boundary
conditions. Generalized differential quadrature method used to solve the
governing equation. The effects of some parameters, such as small-scale
parameters and constant material parameters are studied