Dynamic and Quasistatic Properties of an Auxetic Structure: A Comparative Study

Abstract

A hybrid auxetic structure, named re‐entrant chiral auxetic structure (RCA), is recently developed based on topological features of both re‐entrant and chiral auxetic honeycombs. Herein, the in‐plane quasistatic and dynamic performances of the RCA are compared. Experimental specimens for both the quasistatic and dynamic tests are designed to have identical dimensions and fabricated from polyamide12 (PA12) using an additive manufacturing process, Multi Jet Fusion (MJF). Compressive tests are conducted at constant velocities of 0.066 mm s−1 on a Zwick Roell machine and of 5 m s−1 on an Instron VHS 8800 high‐speed machine for quasistatic and dynamic compressions, respectively. Numerical models are developed using ABAQUS/Explicit and verified by experiments. Results evidence that performances of the RCA are sensitive to the crushing velocity. Moreover, the base material (PA12) displays poor ductility under impact loads; therefore, fracture of the structural members dominates the deformation of the structure when it is dynamically crushed. Energy absorption of specimens that are quasistatically crushed outperforms those under dynamic compression. Furthermore, discrepancy in Poison's ratio curves is observed under quasistatic and dynamic tests due to the change in the deformation modes.