MACHINE DIRECTION STRENGTH THEORY OF CORRUGATED FIBERBOARD

Linerboard elements between the corrugations of corrugated fiberboard can be viewed as short wide columns when the fiberboard is loaded perp endicular to the axes of the corrugations. Column ends are elastically restrained by the corrugated medium. A theory of buckling of nonlinea r corrugated fiberboard material, with compression perpendicular to th e corrugation axes, was developed. This theory is consistent with a pr evious theory applied to fiberboard with compression parallel to the c orrugations. The theory matched strength data of corrugated fiberboard using paper compression strength, extensional stiffness, and bending stiffness data as inputs. The theory was further improved by empirical ly correcting for interactions between material crush failure and stru cture buckling failure. The correction equation predicts an optimum fo rm of the linerboard stress-strain curve from initial slope and maximu m stress data and predicts an element slenderness that varies with the mode of failure.