Design of an auxetic cellular structure with different elastic properties in its three orthogonal directions

Auxetic structures have become one of the most studied types of cellular structure in recent years, thanks to their highly specific mechanical properties. Most microstructures are designed with homogeneous properties in their main axes; however, in this research, we propose an innovative asymmetric 3D auxetic structure based on a 2D configuration of cells drawn from the literature. The new auxetic cell is designed by topology analysis using classical Timoshenko beam theory. To validate the design, samples were constructed by fused filament fabrication with ABSplus, and tested under quasi-static compression to determine Young's modulus in the three orthogonal directions. The experimental results show good agreement with the topological analysis and reveal that the proposed cell can transmit a different mechanical behavior to the macrostructure in its three orthogonal directions.