Mechanical behavior of sandwich composite beams made of foams and functionally graded materials

We investigate sandwich composite beams using a direct approach which models slender bodies as deformable curves endowed with a certain microstructure. We derive general formulas for the effective stiffness coefficients of composite elastic beams made of several non-homogeneous materials. A special attention is given to sandwich beams with foam core, which are made of functionally graded or piecewise homogeneous materials. In the case of small deformations, the theoretical predictions are compared with experimental measurements for the three-point bending of sandwich beams, showing a very good agreement. For functionally graded sandwich columns we obtain the analytical solutions of bending, torsion and extension problems and compare them with numerical results computed by the finite element method.

► The paper deals with elastic composite beams modeled by the direct approach. ► Analytical formulas for the effective stiffness coefficients are obtained. ► General non-homogeneous multilayered beams, isotropic or orthotropic, are analyzed. ► Theoretical and experimental results are compared for bending of sandwich beams. ► For functionally graded sandwich columns analytical and numerical results are given.