Failure behavior of star-shaped zero Poisson's ratio honeycomb core with aluminum face-sheet sandwich beams under three-point bending

Abstract

The failure behavior and energy absorption performance of star-shaped zero Poisson’s ratio honeycomb core with aluminum face-sheet sandwich beams under three-point bending are experimentally and numerically studied. A numerical model that accounts for the nonlinear mechanical behavior of phenolic resin-impregnated aramid paper is developed, and its accuracy is validated using experimental stiffness and peak load data, yielding maximum errors of 13.40% and 3.26%, respectively. The influence of key geometric parameters on the load-carrying capacity, energy absorption and failure mechanisms of honeycomb sandwich beams is systematically analyzed. Results demonstrate that increasing the face-sheet thickness, honeycomb core height, honeycomb cell wall thickness or reducing the side length of the honeycomb cell can improve both the structural loadcarrying capacity and energy absorption. When the core height is held constant, the initial failure mode transitions progressively from face-sheet indentation to core shear failure with increasing face-sheet thickness. Furthermore, the overall bearing capacity of the sandwich beam is improved with the increase in core height, ranging from 2335 N at d = 16 mm to 2943 N at d = 22 mm. However, core height effect on structural stiffness is less pronounced compared to that of the face-sheet thickness. It is worth noting that core shear consistently dominates the failure response across all specimens regardless of variations in core height.