Design of a Recessed Honeycomb Structure with a Nested Star Configuration and Study of Its Static Mechanical...

Negative Poisson's ratio materials show great potential in aerospace, automotive engineering, and military protection owing to their unique deformation behavior and superior mechanical properties. Nevertheless, current negative Poisson's ratio honeycomb structures suffer from an inherent conflict between stiffness and energy absorption, along with poorly understood mechanical regulation mechanisms in complex three-dimensional nested configurations. To address these issues, this paper proposes a novel Cross Re-entrant Hexagon Nested Star-shaped Cell (CRNSC). Through theoretical derivation, finite element simulation, and quasi-static compression experiments, the mechanical properties and energy absorption characteristics of the structure are systematically investigated. A geometric characterization system based on length, angle, and thickness parameters is established. The results show that the cell wall thickness significantly increases the relative density, while the angle θ between the inner inclined strut and the horizontal line induces polarity reversal of the Poisson's ratio. The outer inclined strut angle α and the inner angle θ exhibit monotonic or nonlinear regulatory effects on the equivalent Poisson's ratio and the effective Young's modulus, respectively. The optimal load-bearing configuration (α = 65°, θ = 35°) achieves a peak stress of 1.01 MPa, and the optimal deformation configuration (α = 55°, θ = 25°) reaches an ultimate strain of 4%. Theoretical, simulated, and experimental results are in good agreement with errors below 7%, validating the model's effectiveness.