Theory of thin-walled functionally graded sandwich beams with single and double-cell sections

In the present work, a computational model has been presented to study the flexural and torsional analyses of thin-walled functionally graded sandwich beams with single and double-cell sections. The analysis model is based on the Euler-Bernoulli beam theory and includes the effects of elastic couplings and constrained warping. The mechanical properties of beam such as Young's and shear moduli are assumed to continuously vary in the thickness direction based on the power law distribution of volume fraction of ceramic or metal. To solve the flexural and torsional problems of functionally graded material (FGM) sandwich box beams, the finite beam element considering Hermite cubic interpolation polynomials is employed with the scope to discretize the governing equations. The theory is validated against the analytical solutions and the finite element analysis results for beams with single and double-cell box sections. Three types of material distribution are considered to investigate the effects of gradient index, thickness ratio of ceramic, material ratio, and width-to-height ratio on the various rigidities of cross-section of FGM sandwich box beams. Numerical results show that the above mentioned effects play important role on the structural responses of FGM sandwich box beams.