A Mechanistic Perspective of the Biaxial Strength of Paperboard

Prior research has demonstrated the practical significance of biaxial strength and established methods for measuring and predicting biaxial properties. Analytical models have been shown to accurately predict failure conditions, but do not identify the mode of failure. The present research develops a method for modeling the biaxial strength of paperboard based on criteria which infer a specific mechanism or mode of failure. In this approach, one or more criteria comprise a model which is evaluated iteratively at multiple states of stress to construct a failure envelope. Analytical results are graphically compared with experimental data. While some models evaluated in this report do not adequately represent the data, one comprised of both stress and strain limiting criteria yields an acceptable fit. We conclude that the modeling approach proposed is practical and useful for distinguishing between “potentially correct” and “inadequate” concepts of biaxial strength. Results suggest that transverse compressive strain may play a role in limiting tensile strength and that paperboard may not fail in an in-plane shear mode unique from normal tensile and compressive failure.