Geometric Optimization and Mechanical Performance Enhancement of Auxetic Structures for High‐Impact Applications Through Fused Deposition Modeling

This study investigates the mechanical performance of three auxetic structures: re‐entrant, re‐entrant‐star hybrid, and S‐shape, to identify the most effective design for high‐impact applications. Among these, the re‐entrant‐star hybrid structure demonstrates superior specific energy absorption (SEA), achieving 0.92 ± 0.12 J g −1 , attributed to its combination of re‐entrant and star‐shaped elements, which enhances both energy dissipation and structural integrity. In contrast, the re‐entrant and S‐shaped structures recorded SEAs of 0.80 ± 0.02 and 0.19 ± 0.05 J g −1 , respectively. The hybrid structure also exhibits the highest crush force efficiency (CFE) and equivalent plateau stress (EPS), highlighting its ability to maintain consistent load‐bearing capacity and to sustain stress during compression. Flexural and impact tests further validate the hybrid structure's performance, with notable improvements in bending strength and impact resistance. To further enhance its performance, finite element analysis (FEA) simulations are conducted to optimize geometric parameters, specifically strut thickness and inclination angle, to maximize mechanical performance. Postoptimization, the SEA of the re‐entrant‐star structure increases by 449%, EPS by 3400%, and in‐plane flexural modulus by 514%. These results demonstrate the effectiveness of optimizing geometric parameters to maximize the mechanical performance of auxetic structures for applications requiring high‐energy absorption.