Special features inherent in static behavior and free vibration response of sandwich beams with a transversely flexible ("soft") core are discussed. The analytical formulation is based on a higher-order theory for sandwich panels (HSAPT). The numerical procedure permits imposition of different support conditions at the same boundary section, and does not rely on the use of presumed displacement patterns and de-coupling techniques, a common feature in sandwich analyses, and. The non-sinusoidal modes confined to the support zones of the beam may occur at critical static load levels much lower than those predicted on the basis of presumed harmonic modes. Soft-core sandwich beams exhibit a complex branching behavior under static loads, including limit points and secondary bifurcation phenomena. The face sheet deflections of the free vibrating sandwich beams with nonidentical support conditions at the same boundary are different in the close vicinity of that boundary. There are sandwich beam layouts for which some higher vibration modes arise from the interaction of the symmetric and anti-symmetric vibration modes. Examples of the static and free vibration response of soft-core sandwich beams show that they behave as compound structures in which local/localized, overall or interactive forms of the response can take place depending on the geometry, mechanical properties, and boundary conditions.
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