Large deformation behavior and energy absorption of rotating square auxetics
Fereshteh Hassani, Zia Javanbakht, Sardar Malek
Abstract
This study focuses on large deformation in-plane response of rotating square (RS) auxetics under quasi-static tension with an emphasis on their energy absorption (EA). First, metallic RS samples were fabricated and tested under uniaxial tension and the results were used to establish validated numerical models using ANSYS. Gurson–Tvergaard–Needleman (GTN) model was employed to evaluate the ductile damage and its capability to predict failure of the RS structure was investigated. Numerical analyses were then conducted to compare the large tensile responses of a regular RS (R-RS) and a bio-inspired RS (Bio-RS-0) introduced by Sorrentino et al. (2022). Subsequently, a parametric study evaluated the effect of the size of a circular perforation in the square region of the Bio-RS-0 on the stress distribution, force–deformation response, failure mechanism, and specific energy absorption (SEA) of the structures. Bio-RS-0 enhanced the SEA of R-RS by more than 250% due to the increased engagement of the geometry in plastic deformation . Large perforations significantly influenced the response in larger strains and their failure mode. Two failure mechanisms were identified which could be adjusted by perforation size. An optimum perforation size and the corresponding failure mode were identified for maximum SEA. Potential applications for energy absorbing auxetics in tension were discussed at the end.