The importance of the size effect on the critical buckling loads of sandwich beams

Sandwich structures are frequently used in many industrial applications such as aerospace, aviation, maritime, electrical-electronics, automotive and construction sectors, as they have high rigidity and strength, while being light. Recently, with the rapid developments in nanotechnology, these types of structures have also been used in micro and nano electromechanical systems. In order to get the best efficiency from these structures, their mechanical behavior (such as bending, buckling and vibration) must be known exactly. In this thesis, the buckling behavior of a simply supported functionally graded sandwich microbeam under the effect of axial compressive load is investigated. A sandwich microbeam consisting of homogeneous ceramic core and functionally graded surfaces is considered. The governing differential equations and related boundary conditions are obtained with the help of the modified couple stress theory and the minimum total potential energy principle based on Bernoulli-Euler, parabolic, Timoshenko and improved Timoshenko beam theories. Using the Navier solution method, the critical buckling load of a simply supported sandwich microbeam subjected to axial compressive load is calculated. The effects of size scale parameter, material change index, slenderness ratio and shear deformation on the critical buckling load values were investigated in detail.