Dynamic and Quasi‐Static Properties of an Auxetic Structure: A Comparative Study

A hybrid auxetic structure named a re-entrant chiral auxetic structure (RCA) was recently developed based on topological features of both re-entrant and chiral auxetic honeycombs. In this study, the in-plane quasi-static and dynamic performances of the (RCA) are compared. Experimental specimens for both the quasi-static and dynamic tests were designed to have identical dimensions and fabricated from polyamide12 (PA12) using an additive manufacturing process, Multi Jet Fusion (MJF). Compressive tests were conducted at constant velocities of 0.066 mm/s on a Zwick Roell machine and of 5 m/s on an Instron VHS 8800 high speed machine for quasi-static and dynamic compressions, respectively. Numerical models were developed using ABAQUS/Explicit and verified by experiments. Results evidenced that performances of the RCA were sensitive to the crushing velocity. Moreover, the base material (PA12) displayed poor ductility under impact loads, therefore, fracture of the structural members dominates the deformation of the structure when it was dynamically crushed. Energy absorption of specimens that were quasi-statically crushed outperformed those under dynamic compression. Furthermore, discrepancy in Poison’s ratio curves was observed under quasi-static and dynamic tests due to the change in the deformation modes. This article is protected by copyright. All rights reserved.