Synergistic energy absorption in hybrid auxetic sandwich panels: A parametric study of combined positive–negative poisson's ratio cores fabricated via fused deposition modeling

Abstract

This study investigates the design, fabrication, and quasi-static compressive behavior of corrugated sandwich panels with auxetic cores manufactured via fused deposition modeling (FDM) using polylactic acid (PLA). Three core topologies, hexagonal honeycomb (positive Poisson's ratio), re-entrant (negative Poisson's ratio), and hybrid (combining both) were systematically evaluated for energy absorption capacity while maintaining a constant relative density. The hybrid core demonstrated superior performance. When tested as a corrugated sandwich panel (core + corrugated skins), the hybrid configuration achieved a specific energy absorption (SEA) of 7.49 J/g, which exceeded that of the honeycomb sandwich panel (4.82 J/g) and re-entrant sandwich panel (5.35 J/g) by 55% and 40%, respectively. These values refer to the full sandwich panel; the core-only SEA values were lower (1.89–4.70 J/g), as the skins and corrugation geometry contribute additional structural stability and energy dissipation. Taguchi optimization identified the optimal FDM printing parameters as a $\pm {45}^{\circ }$ raster angle, a printing speed of 4000 mm/min, and a layer thickness of 0.2 mm to maximize ultimate tensile strength (UTS) and energy absorption per unit volume (EA) in the printed PLA material. Finite element simulations showed strong agreement with experimental results, with force-displacement curve deviations below 10% for the hybrid core, accurately predicting deformation modes and progressive collapse behavior. The unique deformation mechanism of the hybrid core combining progressive collapse from honeycomb regions and inward buckling from re-entrant regions enhances energy dissipation while maintaining structural stability, making it a promising candidate for lightweight quasi-static energy absorption applications.