Lateral instability of sandwich beams under uniform bending

This paper investigates the lateral-torsional instability of soft-core sandwich beams. This physical phenomenon, which has received limited attention in the framework of sandwich structures, is investigated here in the context of fully nonlinear analysis for the first time. The research addresses, quantifies, and explores the lateral-torsional instability with emphasis on the unique features of the sandwich structure and its geometrically nonlinear response. The research questions relate to the nature of the instability and to the role of the deformability of the core layer in the unique mechanism. The results of the investigation include a new, high-order, nonlinear model for the analysis of the torsional-lateral response as well as new insight into the evolution of the phenomenon in sandwich beams.