  In this paper, strain gradient elasticity formulation for analysis of FG
(Functionally Graded) micro-cylinders is presented. The material properties are
assumed to obey a power law in radial direction. The governing differential
equation is derived as a fourth order ODE. A power series solution for stresses
and displacements in FG micro-cylinders subjected to internal and external
pressures is obtained. Numerical examples are presented to study the effect of
the characteristic length parameter and FG power index on the displacement
field and stress distribution in FG cylinders. It is shown that the
characteristic length parameter has a considerable effect on the stress
distribution of FG micro-cylinders. Also, increasing material length parameter
leads to decrease of the maximum radial and tangential stresses in the
cylinder. Furthermore, it is shown that the FG power index has a significant
effect on the maximum radial and tangential stresses.
