Global Buckling of Sandwich Beams Based on the Extended High-Order Theory

The focus of this paper is the application of the recently introduced extended high-order sandwich panel theory to the global buckling of a sandwich beam/wide panel. Three different solution approaches using the extended high-order sandwich panel theory are presented to investigate the effects of simplifying the loading case by applying loads just on the face sheets and by including or excluding nonlinear axial strains in the core. The results are also compared with results from a benchmark elasticity solution and, furthermore, from the simple sandwich buckling formula by the earlier extended high-order sandwich panel theory. It is found that all three theories are close to the elasticity solution for soft cores with E-I(c)/E-1(f) < 0.001. However, for moderate cores, i.e., with E-I(c)/E-1(f) > 0.001, the theories diverge and the extended high-order sandwich panel theory is the most accurate.