Mechanical metamaterials with a negative Poisson's ratio, commonly referred to as auxetic materials, have attracted increasing attention due to their unconventional deformation mechanisms and enhanced energy absorption capabilities. In this study, a comprehensive numerical investigation of the mechanical properties of four two-dimensional star-shaped auxetic structures is presented. In addition to the conventional 2D arc star-shaped (2D-AS), improved 2D arc star-shaped (i2D-AS), and classical star-shaped (2D-SS) structures, a novel tangent 2D arc star-shaped structure (t2D-AS) is proposed by modifying the geometry of the original 2D-AS configuration. Finite element simulations were performed using periodic boundary conditions to evaluate the negative Poisson's ratio and Young's modulus under uniaxial loading for different sets of geometric parameters. The numerical model was validated through comparison with available theoretical results for selected structures, demonstrating good agreement. The obtained results indicate that the newly introduced t2D-AS structure exhibits the lowest relative density among the analyzed configurations, while maintaining auxetic behavior and competitive stiffness characteristics. Furthermore, the influence of mesh density and the number of unit cells on the calculated Poisson's ratio was investigated using 𝑛 ×𝑛 models, confirming the robustness and consistency of the numerical approach. The findings of this study provide valuable insights into the structure property relationships of star-shaped auxetic metamaterials and establish a solid foundation for future analytical modeling, experimental validation, and energy absorption analyses.
Sinđelić et al. (Thu,) studied this question.