Defect sensitivity of 2D lattice materials with positive, zero, and negative Poisson’s ratios

Two-dimensional (2D) lattice materials with well-designed microstructures exhibit extraordinary properties such as zero and negative Poisson’s effects, and play a crucial role in industrial fields. However, inevitable defects from manufacturing, storage, transportation, and service may compromise their microstructures and functionalities. Therefore, it is important but still unclear: which microstructures and associated properties are most or least sensitive to defects. The current study investigated the effects of bar-missing/broken defects on the elastic properties of six typical honeycomb structures—Hexagonal Honeycomb, Diamond Honeycomb, Semi-Re-Entrant Honeycomb, Four-Pointed Star Honeycomb, Re-Entrant Honeycomb, and Double Arrowhead Honeycomb— which are categorized into positive, zero, and negative Poisson’s ratio groups. A finite element model incorporating the random distributed defects was developed and the imperfection sensitivity coefficient was defined to quantitatively analyze the sensitivity of elastic properties to missing bars. The results show that the shear modulus of Double Arrowhead Honeycomb and Re-Entrant Honeycomb, and the vertical modulus of Semi-Re-Entrant Honeycomb are most sensitive to the defects, while Four-Pointed Star Honeycomb demonstrates the highest flaw tolerance overall. The underlying mechanisms for defect-sensitivity or flaw-tolerance are closely related to the deformation mode and nodal connectivity of these lattice structures.

For more details, please refer to our paper by the link below:
https://doi.org/10.1016/j.compositesa.2025.109215