Design, analysis and optimization of the uniaxial properties of a new auxetic anti-chiral parallelogram metamaterial

•Designed an innovative 2D auxetic anti-chiral parallelogram metamaterial.•Established analytical and numerical models for in-plane mechanical properties.•Utilized the NSGA-Ⅱ optimization algorithm for designing mechanical metamaterials.•Conducted experimental and numerical validation to ensure the accuracy of the optimal results.•Evaluated the energy absorption performance of the new metamaterial for different parameters. An innovative two dimensional auxetic metamaterial was designed by mirroring a parallelogram with two parallel ligaments along the horizontal and vertical directions. The architecture of the metamaterial is based on the adoption of a structural chiral deformation mechanism induced by the rotation of the connecting joint of the parallel ligaments. A parametric study was performed to investigate the in-plane equivalent mechanical properties of this anti-chiral parallelogram (ACP) metamaterial and auxetic parallelogram honeycombs from open literature using theoretical and numerical models. The NSGA-Ⅱoptimization algorithm has also been adopted to identify the optimal Pareto fronts for the maximum non-dimensional Young's modulus and minimum Poisson's ratios for the two classes of auxetic metamaterials. The optimization process indicated that the new ACP metamaterial possessed larger stiffness within specific ranges of Poisson's ratios. Quasi-static compressive experimental tests in linear and nonlinear regimes with finite element simulations have been carried out to verify the results of the optimal configurations . The energy absorption performance of the new ACP metamaterial has been also evaluated for different combinations of parameters. The good tunability of the mechanical properties of this new auxetic metamaterial suggest potential engineering applications for general biomedical prosthesis and energy absorption purposes.