The role of filleting on the stressed state of a square grid auxetic structure

Auxetic structures attain certain abnormal mechanical attributes such as negative Poisson’s ratios due to the macro level structural forms. Achieving the auxetic responses is often the central focus of the design of any auxetic structural form. However, the stress distribution across the structures and in particular, the stress concentration aspects are often paid little attention. A numerical simulation analysis is conducted in this paper to establish the stress distribution patterns as well as the stress concentration effects based on variations in the filleting around the critical points of the structure. A square grid auxetic structural form is selected and finite element simulation of the stress fields indicated specific roles of the slight geometrical modifications in terms of filleting leading to variations in both peak stresses and the locations of the stress concentration points. Optimum fillet dimensions could be established based on the results of the numerical experiments.