Compressive behaviour of corrugated board panels

The compressive responses and failure mechanisms of corrugated sandwich panels subjected to uniform lateral compression are examined by a combined theoretical and experimental study. Particular focus is placed on illuminating the role of the initially sinusoidal fluting in dominating the overall deformation and local collapse of the board panel. Two types of specimen are considered, FCT (Flat Crush Test) specimen and CMT (Concorra Medium Test) specimen; the former is cut directly from the panel whilst the latter consists of a fluting, a thin glued tape but no outliners (face sheets). Both specimens are modelled by curved beam elements and surface contact elements (including sticky contact elements for the CMT specimen), and the elastoplastic material is idealised by a bi-linear constitutive model satisfying the J(2)-flow theory. Finite element calculations are first made to study the effect of replacing the periodic boundary conditions with free-edge boundary conditions on the deformation of a unit cell. Extensive calculations are then performed to obtain the compressive strength of each specimen as a function of geometrical and material parameters, and to study the global and local plastic collapse mechanism during the deformation process. The effect of manufacturing-induced geometrical imperfections on the mechanical properties of the board panel is also quantified. Experimental measurements are conducted on two types of commercially available corrugated board panel to check the validity of analytical predictions.