Computational optimization of modified honeycomb structures for enhanced auxetic and energy absorbing performance

This study investigates the mechanical behavior of modified honeycomb structures, focusing on auxetic behavior, characterized by a negative Poisson’s ratio (NPR). Finite element analysis (FEA) was employed to evaluate the effects of various design parameters on Poisson’s ratio and Young’s modulus across three types of unit cell: hollow-wall, hybrid, and solid-wall. The influence of geometric variations and material stiffness was analyzed to assess their impact on auxetic behavior and structural stiffness. Results show that hollow-wall unit cells exhibit the highest auxetic response. Conversely, filling the side cuts with base materials reduces rotational deformations and diminishes auxetic effects. However, filling with stiffer materials enhances auxetic behavior by acting as rigid constraints, amplifying rotational and bending deformations in adjacent flexible regions. Strain energy density (SED) analysis reveals that hybrid unit cells can maximize elastic strain energy density during deformation by balancing flexibility and stiffness, indicating their suitability for energy absorption applications. Additionally, while increasing the stiffness of the filler material initially enhances auxetic behavior and elastic strain energy storage, further increases yield negligible effects. These findings provide valuable insights for optimizing cellular structures in applications requiring tailored mechanical performance, such as structural reinforcement, enhanced auxetic behavior, and improved energy absorption.