Enhanced tensile performance and energy absorption in elliptic-profile re-entrant honeycombs

This study introduces a novel elliptic-profile re-entrant honeycomb (ERH) structure designed to address the limitations of traditional auxetic designs in tensile performance and energy absorption. The ERH panel incorporates smoothly varying curvature to reduce stress concentrations and promote uniform deformation under tensile loading. A two-dimensional equivalent model (2D-EKM), developed using the variational asymptotic method, accurately predicts the panel’s elastic behavior and is validated against experimental data from uniaxial tensile tests on 3D-printed specimens, as well as high-fidelity finite element simulations. Results show that the ERH design enables a gradual transition from bending- to stretching-dominated deformation, enhancing stiffness while maintaining auxeticity. As a result, the ERH panel achieves a 64% higher elastic modulus, 73% greater tensile energy absorption, and 83% improvement in specific energy absorption compared to arc-shaped counterparts. Parametric analyses further identify optimal geometric configurations—specifically, a major-to-minor axis ratio of 1.9, a cellular aspect ratio of 1.0, and a slenderness ratio of 1.5—as key to maximizing mechanical efficiency. This study proposes a structurally innovative ERH design that not only enhances mechanical and energy absorption properties but also offers promising applications in impact mitigation and multifunctional lightweight structures. • A novel elliptic-profile re-entrant honeycomb is proposed for tensile energy absorption. • The ERH transitions from bending- to stretching-dominated deformation under tension. • A VAM-based equivalent model is developed for ERH structures under tensile loading. • The ERH shows a 64% increase in stiffness and 83% in SEA over existing designs. • The elliptical curvature enables uniform stress redistribution at critical junctions.