The out-of-plane compressive behavior of auxetic chiral lattice with circular nodes

Auxetic metamaterials have many exceptional mechanical properties due to their counter-intuitive deformation characteristics. However, most studies on auxetic metamaterials focus on in-plane properties while auxetic metamaterials are inevitably affected by out-of-plane forces in practical applications. In this study, the out-of-plane mechanical properties and deformation patterns of a recently proposed auxetic structure, the chiral lattice with circular nodes (NCL), were investigated numerically and experimentally under quasi-static uniaxial compression. It also took truss lattice and traditional chiral lattice (TCL) as benchmarks to compare. The results showed that the energy absorption capacity of the NCL structure in the out-of-plane direction was superior to that of the other two benchmarks. The energy absorption (EA) and specific energy absorption (SEA) of the TCL structure and the truss lattice structure were roughly close, compared with the TCL structure, the EA and SEA of the NCL structure were improved by 34.1% and 13.3%, respectively. In addition, parametric studies were carried out to investigate the effects of geometric parameters and volume fraction of the frame on the structural deformation patterns and mechanical properties.