Mechanical and thermal buckling analysis of functionally graded sandwich beams with foam core using different beam theories

Using various beam theories, this study investigates the buckling of sandwich beams with functionally graded faces and a foam core subjected to either thermal or mechanical loading. The mechanical properties of materials constituting the sandwich beams are tailored to vary smoothly from the bottom to the top surfaces. For thermal buckling, three typical types of temperature distribution are considered: uniform, linear, and nonlinear temperature distributions. The minimum potential energy is employed to derive the governing equations and the trigonometric admissible functions-based Ritz method is adopted to discretize these equations for the approximate solution. A convergence study is performed to determine the appropriate number of terms in the admissible functions. Comparison studies are conducted to validate the results of the current study. In addition, the effects of beam theories, material distribution, slenderness ratio, temperature distributions, porosity coefficient, boundary conditions, and layer thickness ratio on the buckling of the beams are examined. Numerical results reveal that beam theories have a significant influence on the buckling behavior of sandwich beams with a foam core.