Viscoelastic Creep Compliance and Interfacial Fracture Energy in Paperboard Laminates
Creep compliance dictates long-term carton deformation, while interfacial fracture energy governs delamination under score bending and pallet loads.
Mckee Box Compression Formula
Predictive Equation
Standardised structural calculations estimate the peak top-to-bottom load capacity of a finished corrugated fiberboard container using sheet material properties. The mckee box compression formula connects the edge compression test value and flexural stiffness of the board directly to the carton’s load-bearing limit. This model allows designers to estimate performance before manufacturing begins.
Structural Variables
Material performance is evaluated through the edge crush test value alongside the flexural stiffness of the board in both the machine and cross directions. The mckee box compression formula calculates the resistance based on these parameters and the perimeter of the box. By incorporating both stiffness and compression values, it accounts for the buckling of the panels under vertical loads.
Modern packaging laboratories use these calculations to optimize paperboard selection for transport cartons.
Design Application
Accurate performance predictions reduce the need for expensive physical testing protocols. While the standard equation works well for simple rectangular slotted containers, adjustments are needed for boxes with ventilation holes or complex structural designs. High humidity environments reduce the board’s stiffness, which must be factored into the safety margins during stacking calculations.
Packaging engineers rely on this formula to select the lowest grammage board that will safely support the pallet load. This keeps material costs to a minimum while preventing catastrophic collapse during warehouse storage.