Buckling behavior and mechanical performance of corrugated board boxes reinforced by polylactic acid grid printing: towards lightweight packaging

This study investigates printing poly lactic acid (PLA) reinforcement grids on corrugated board boxes as a strategy to enhance their mechanical performance-to-weight ratio, with the objective of decreasing overall material consumption. Four-points bending and compression tests were respectively conducted on plates printed with varying thicknesses and on boxes printed either inside or outside. Stereo digital image correlation (DIC) was employed during compression to monitor panel deflection amplitudes. Increasing the height of printed grids induced an improvement of the bending stiffness-to-weight ratio. While outside-printed boxes showed a 26% BCT increase for a 21% mass increase, inside-printed boxes exhibited a 9% BCT increase but a stable post-BCT behavior, being able to withstand important loads before their ultimate collapse. They exhibited crushing of their panel, contrary to the other box families. Deflection amplitudes measured by DIC were plotted as function of load to further analyze compression behaviors, initial imperfections and buckling loads across the different box families. It revealed that PLA shrinkage during cooling induced initial imperfections, driving printed panels into the post-buckling range, and accelerating their deflection despite their increased bending stiffness. DIC data were used to calibrate an analytical buckling model highlighting the role of initial imperfections in panels deflection evolution.