The subject of the study is the auxetic behavior of the cellular structure under compressive and tensile loads. This study experimentally assessed the auxetic properties of hourglass-shaped cellular structures. The experiments were conducted using 3D-printed polymer samples. The Poisson ratios of the structures in the compression tests were -0.06 for PLA samples and -0.05 for ABS. Two types of PLA samples with different shoulder structures were used in the tension tests. Type 1 samples had monolithic shoulders, whereas type 2 samples had cellular shoulders. The average tensile strength of the type 1 samples was 0.482 kN, whereas that of the type 2 samples was 0.416 kN, which was 13.7% lower. The elongation at failure was 35% higher in the type 2 samples (1.85 mm and 1.37 mm, respectively) than in the type 1 samples. The presence of an auxetic mesh over the entire sample contributed to the high deformation capacity of the sample. In further research, it is planned to create samples of fine-grained concrete with cellular structure.

This study investigates the properties of structures with an ordered cellular internal configuration. Certain forms of the ordered internal structure contribute to the manifestation of auxetic properties. In this study, a hexagonal hourglass cell shape was chosen. The samples were 3D-printed with PLA and ABS filaments. The panels were subjected to out-of-plane compression. The Poisson ratio of the panels under compression was −0.06 for PLA samples and −0.05 for ABS samples. Tension tests were performed using two types of samples: type 1 with monolithic shoulders and type 2 with cellular shoulders. The average tensile strength of the type 1 samples was 0.482 ± 0.006 kN, whereas that of the type 2 samples was 0.416 ± 0.028 kN, which was 13.7% lower. The elongation at failure in the type 2 samples was 35% higher than that in the type 1 samples (1.85 ± 0.14 mm and 1.37 ± 0.08 mm, respectively). The higher deformation capacity of type 2 samples may be explained by the presence of an auxetic mesh over the entire sample. Auxetic properties are useful in numerous engineering fields. For civil engineering purposes, the blast-proof abilities of such structures are important. Thus, in future research, it is planned to create samples of fine-grain concrete with similar cellular structure.